This spec is incomplete and it is not expected that it will advance beyond draft status. Authors should not use most of these features directly, but instead use JavaScript editing libraries. The features described in this document are not implemented consistently or fully by user agents, and it is not expected that this will change in the foreseeable future. There is currently no alternative to some execCommand actions related to clipboard content and contentEditable=true is often used to draw the caret and move the caret in the block direction as well as a few minor subpoints. This spec is to meant to help implementations in standardizing these existing features. It is predicted that in the future both specs will be replaced by Content Editable and Input Events.
This document defines the behavior of the editing commands that can be
executed with execCommand.
The APIs specified here were originally introduced in Microsoft's Internet Explorer, but have subsequently been copied by other browsers in a haphazard and imprecise fashion. Although the behavior specified here does not exactly match any browser at the time of writing, it can serve as a target to converge to in the future.
Where the reasoning behind the specification is of interest, such as when major preexisting rendering engines are known not to match it, the reasoning is available by clicking the "comments" button on the right (requires JavaScript). If you have questions about why the specification says something, check the comments first. They're sometimes longer than the specification text itself, and commonly record what the major browsers do and other essential information.
The principles used for writing this reference list are:
<b> for bold (if the CSS styling flag is
false), and convert <strong> and
<span style="font-weight: bold"> if we
happen to be modifying that node anyway.
Tests can be found here.
This specification is mostly feature-complete. It should be considered mostly stable and awaiting implementater review and feedback.
Significant known issues that I need feedback on, or otherwise am not planning to fix just yet:
I haven't paid much attention to performance. The algorithms here aren't performance-critical in most cases, but I might have accidentally included some algorithms that are too slow anyway on large pages. Generally I haven't worried about throwing nodes away and recreating them multiple times or things like that, as long as it produces the correct result.
If it would be useful to implementers for me to spend time and spec complexity on avoiding some of the masses of useless operations that are currently required, please say so. All intermediate DOM states are black-box detectable via mutation events or whatever their replacement will be, so implementers theoretically can't optimize most of this stuff too much themselves, but in practice I doubt anyone will rely on the intermediate DOM states much.
<span style=font-weight:bold> instead of
<b>, while if it's off, it produces stuff
like <font color=red> instead of
<span style=color:red>. The issue is that
authors might want a mix, like making the markup as concise as possible
while still conforming, and they can't do that. Changing the flag on a
per-command basis doesn't help because of things like the "restore the
values" algorithm, which might create several different types of style
at once and has to use the same styling flag for all of them. This was
discussed back in March in
this thread, along with a number of other things, but at that
time I hadn't written commands that change multiple styles at once,
so it seemed feasible to ask authors to switch styleWithCSS on or off
on a per-command basis.
A variety of other issues are also noted in the text, formatted like this. Feedback would be appreciated on all of them.
TODO:
Also TODO: Things that are only implemented by a couple of browsers and may or may not be useful to spec:
Things I haven't looked at that multiple browsers implement:
Things that would be useful to address for the future but aren't important to fix right now are in comments prefixed with "TODO".
This specification defines a number of commands, identified by ASCII case-insensitive strings. Each command can have several pieces of data associated with it:
execCommand(). Every command defined in this specification has an
action defined for it in the relevant
section. For example, the bold command's action generally
makes the current selection bold, or removes bold if the selection
is already bold. An editing toolbar might provide buttons that
execute the action for a command if clicked, or a script might run an
action without user interaction to achieve
some particular effect. Actions return either true or false, which
can affect the return value of execCommand().
queryCommandIndeterm(),
depending on the current state of the document. Generally, a
command that has a state defined will be indeterminate if the state is true for part but not all of the current
selection, and a command that has a value defined will be indeterminate if different parts of the
selection have different values.
An editing toolbar might display a button or control in a special
way if the command is indeterminate, like showing a "bold" button as
partially depressed, or leaving a font size selector blank instead
of showing the font size of the current selection. As a rule, a
command can only be indeterminate if its state is false, supposing it has a state.
queryCommandState(), depending on
the current state of the document. The state
of a command is true if it is already in
effect, in some sense specific to the command. Most commands that have a state
defined will take opposite actions depending on whether the state is true or false, such as making the selection
bold if the state is false and removing bold
if the state is true. Others will just have no
effect if the state is true, like the justifyCenter command. Still others will have the
same effect regardless, like the styleWithCss
command. An editing toolbar might display a button or control
differently depending on the state and
indeterminacy of
the command.
queryCommandValue(), depending on
the current state of the document. A command
usually has a value instead of a state if the property it modifies can take more than
two different values, like the
foreColor command. If the command is indeterminate, its value
is generally based on the start of the selection. Otherwise, in
most cases the value holds true for the entire
selection, but see the
justifyCenter command and its
three companions for an exception. An
editing toolbar might display the value of a
command as selected in a drop-down or filled
in in a text box, if the command isn't
indeterminate.
If you try doing anything with an unrecognized command (except queryCommandSupported), IE10 Developer Preview throws an "Invalid argument" exception. Firefox 15.0a1 throws NS_ERROR_NOT_IMPLEMENTED on querying indeterm/state/value, and returns false from execCommand/queryCommandEnabled. Chrome 19 dev returns false from everything. Opera Next 12.00 alpha throws NOT_SUPPORTED_ERR for execCommand and returns false for enabled/state/value. Originally I went with IE, although of course with a standard exception type. But after discussion (WebKit bug, Mozilla bug), I changed to match WebKit (except that I return "" for value instead of false). The issue is that there are a whole bunch of IE commands that no one else supports or wants to support, and throwing on execCommand() would make lots of pages break. WebKit was unwilling to take the compat risk, so we took the safer option.
Some commands will be supported in a given user agent, and some will not.
All commands defined in this
specification must be supported, except
optionally the copy
command, the cut
command, and/or the paste command. Additional vendor-specific commands can also be
supported, but implementers must prefix any
vendor-specific command names
with a vendor-specific string (e.g., "ms", "moz", "webkit", "opera").
I.e., no trying to look good on lazy conformance tests by just sticking in a stub implementation that does nothing.
A command that does absolutely nothing in a
particular user agent, such that execCommand() never has any effect and
queryCommandEnabled() and
queryCommandIndeterm() and
queryCommandState()
and queryCommandValue() each return the
same value all the time, must not be supported.
In a particular user agent, every command must be consistently either supported or not. Specifically, a user agent must not permit one page to see the same command sometimes supported and sometimes not over the course of the same browsing session, unless the user agent has been upgraded or reconfigured in the middle of a session. However, user agents may treat the same command as supported for some pages and not others, e.g., if the command is only supported for certain origins for security reasons.
Authors can tell whether a command is supported using queryCommandSupported().
At any given time, a supported command can
be either enabled or not. Authors can tell
whether a command is currently enabled using queryCommandEnabled(). Commands that are not enabled do nothing, as described in the definitions of
the various methods that invoke commands.
Testing with bold:
IE10PP2 seems to return true if the active range's start node is editable, false otherwise.
Firefox 6.0a2 seems to always return true if there's anything editable on the page, and throw otherwise. (This is bug 676401.)
Chrome 14 dev seems to behave the same as IE10PP2.
Opera 11.11 seems to always return true if there's anything editable on the page, and false otherwise.
Firefox and Opera behave more or less uselessly. IE doesn't make much sense, in that whether a command is enabled seems meaningless: it will execute it on all nodes in the selection, editable or not. Chrome's definition makes sense in that it will only run the command if it's enabled, but it doesn't make much sense to only have the command run if the start is editable.
It's not clear to me what the point of this method is. There's no way we're going to always return true if the command will do something and false if it won't. I originally just stuck with a really conservative definition that happens to be convenient: if there's nothing selected, obviously nothing will work, and we want to bail out early in that case anyway because all the algorithms will talk about the active range. If there are use-cases for it to be more precise, I could make it so.
Bug 16094 illustrated that we don't really want to be able to modify multiple editing hosts at once, nor do we want to do anything if the start and end aren't both editable, so I co-opted this definition to fit my ends.
Among commands defined in this
specification, those listed in Miscellaneous commands are always
enabled, except for the cut command and
the paste
command. The other commands defined here are enabled if the active
range is not null, its [=range/start node=] is either editable or an [=editing host=], the editing
host of its [=range/start node=] is not an
EditContext
editing host, its [=range/end node=] is either editable or
an [=editing host=], the editing host of
its [=range/end node=] is not an
EditContext
editing host,
and there is some [=editing host=] that is an
[=tree/inclusive ancestor=] of both its [=range/start node=] and its
[=range/end node=].
TODO: Define behavior for show UI.
When the execCommand(command,
show UI, value)
method on the {{Document}} interface is invoked, the user agent must
run the following steps:
For supported: see comment before Supported commands.
For enabled: I didn't research this closely, but at a first glance, this is possibly how Chrome 14 dev and Opera 11.11 behave. Maybe also Firefox 6.0a2, except it throws if the command isn't enabled, I think. IE9 returns true in at least some cases even if the command is disabled. TODO: Is this right? Maybe we should be returning false in other cases too?
If command is not in the Miscellaneous commands section:
We don't fire events for copy/cut/paste/undo/redo/selectAll because they should all have their own events. We don't fire events for styleWithCSS/useCSS because it's not obvious where to fire them, or why anyone would want them. We don't fire events for unsupported commands, because then if they became supported and were classified with the miscellaneous events, we'd have to stop firing events for consistency's sake.
Such an editing host must exist, because otherwise the command would not be enabled.
We have to check again whether the command is enabled, because the beforeinput handler might have done something annoying like getSelection().removeAllRanges().
This new affected editing host is what we'll fire the input event at in a couple of lines. We want to compute it beforehand just to be safe: bugs in the command action might remove the selection or something bad like that, and we don't want to have to handle it later. We recompute it after the beforeinput event is handled so that if the handler moves the selection to some other editing host, the input event will be fired at the editing host that was actually affected.
To map an edit command to input type value, follow this table:
| edit command | inputType |
|---|---|
| backColor | formatBackColor |
| bold | formatBold |
| createLink | insertLink |
| fontName | formatFontName |
| foreColor | formatFontColor |
| strikethrough | formatStrikeThrough |
| superscript | formatSuperscript |
| delete | deleteContentBackward |
| forwardDelete | deleteContentForward |
| indent | formatIndent |
| insertHorizontalRule | insertHorizontalRule |
| insertLineBreak | insertLineBreak |
| insertOrderedList | insertOrderedList |
| insertParagraph | insertParagraph |
| insertText | insertText |
| insertUnorderedList | insertUnorderedList |
| justifyCenter | formatJustifyCenter |
| justifyFull | formatJustifyFull |
| justifyLeft | formatJustifyLeft |
| justifyRight | formatJustifyRight |
| outdent | formatOutdent |
| cut | deleteByCut |
| paste | insertFromPaste |
| redo | historyRedo |
| undo | historyUndo |
When the queryCommandEnabled(command) method on the {{Document}} interface is
invoked, the user agent must run the following steps:
See comment before Supported commands.
When the queryCommandIndeterm(command) method on the {{Document}} interface is
invoked, the user agent must run the following steps:
For supported: see comment before Supported commands.
What happens if you call queryCommand(Indeterm|State|Value)() on a command where it makes no sense?
IE9 consistently returns false for all three. However, any command that has a state defined also has a value defined, which is equal to the state: it returns boolean true or false.
Firefox 6.0a2 consistently throws NS_ERROR_FAILURE for indeterm/state if not supported, and returns an empty string for value. Exceptions include unlink (seems to always return indeterm/state false), and styleWithCss/useCss (throw NS_ERROR_FAILURE even for value).
Chrome 14 dev returns false for all three, and even does this for unrecognized commands. It also always defines value if state is defined: it returns the state cast to a string, either "true" or "false".
Opera 11.11 returns false for state and "" for value (it doesn't support indeterm). Like Chrome, this is even for unrecognized commands.
Gecko's behavior is the most useful. If the author tries querying some aspect of a command that makes no sense, they shouldn't receive a value that looks like it might make sense but is actually just a constant. Originally, I went even further than Gecko: I required exceptions even for value, since doing otherwise makes no sense. But throwing more exceptions is less compatible on the whole than throwing more exceptions, so based on discussion, I switched to a behavior more like Opera, which is more or less IE/WebKit behavior but made slightly more sane.
If command is not supported or has no indeterminacy, return false.
When the queryCommandState(command) method on the {{Document}} interface is
invoked, the user agent must run the following steps:
See comment on the comparable line for queryCommandIndeterm().
Firefox 6.0a2 always throws an exception when this is called. Opera 11.11 seems to return false if there's nothing editable on the page, which is unhelpful. The spec follows IE9 and Chrome 14 dev. The reason this is useful, compared to just running one of the other methods and seeing if you get a NOT_SUPPORTED_ERR, is that other methods might throw different exceptions for other reasons. It's easier to check a boolean than to check exception types, especially since as of June 2011 UAs aren't remotely consistent on what they do with unsupported commands.
Actually, correction: Firefox < 15ish throws an exception if nothing editable is on the page. Otherwise it behaves just like IE/Chrome. See Mozilla bug 742240.
When the queryCommandSupported(command) method on the {{Document}} interface is
invoked, the user agent must return true if command
is supported and available within the current
script on the current site, and false otherwise.
When the queryCommandValue(command) method on the {{Document}} interface is
invoked, the user agent must run the following steps:
This is what Firefox 6.0a2 and Opera 11.11 seem to do when the command isn't enabled. Chrome 14 dev seems to return the string "false", and IE9 seems to return boolean false. For the case where there's no value, or the command isn't supported, see the comment on the comparable line for queryCommandIndeterm().
If command is not supported or has no value, return the empty string.
Yuck. This is incredibly messy, as are lots of other fontSize-related things, but I don't want to define a whole second notion of value for the sake of a single command . . .
If command is "fontSize" and its value override is set, convert the value override to an integer number of pixels and return the legacy font size for the result.
All of these methods must treat their command argument ASCII case-insensitively.
The methods in this section have mostly been designed so that the
following invariants hold after execCommand()
is called, assuming it didn't throw an exception:
queryCommandIndeterm() will return false (or
throw an exception).
queryCommandState() will return the opposite
of what it did before execCommand() was
called (or throw an exception).
queryCommandValue() will return something
equivalent to the value passed to execCommand() (or throw an exception). "Equivalent" here
needs to be construed broadly in some cases, such as fontSize.
The first two points do not always hold for strikethrough or underline, because
it can be impossible to unset text-decoration in CSS. Also, by
design, the state of insertOrderedList and
insertUnorderedList might be true both before
and after calling, because they only remove one level of indentation.
unlink should set the value to null. And
finally, the state of the various justify
commands should always be true after calling, and the value should
always be the appropriate string ("center", "justify", "left", or
"right"). Any other deviations from these invariants are bugs in the
specification.
An HTML element is an {{Element}} whose [=Element/namespace=] is the HTML namespace.
A prohibited paragraph child name is "address", "article", "aside", "blockquote", "caption", "center", "col", "colgroup", "dd", "details", "dir", "div", "dl", "dt", "fieldset", "figcaption", "figure", "footer", "form", "h1", "h2", "h3", "h4", "h5", "h6", "header", "hgroup", "hr", "li", "listing", "menu", "nav", "ol", "p", "plaintext", "pre", "section", "summary", "table", "tbody", "td", "tfoot", "th", "thead", "tr", "ul", or "xmp".
These are all the things that will close a <p> if found as a descendant. I think. Plus table stuff, since that can't be a descendant of a p either, although it won't auto-close it.
A prohibited paragraph child is an HTML element whose [=Element/local name=] is a prohibited paragraph child name.
The block/inline node definitions are CSS-based. "Prohibited paragraph child" is conceptually similar to "block node", but based on the element name. Generally we want to use block/inline node when we're interested in the visual effect, and prohibited paragraph children when we're concerned about parsing or semantics. TODO: Audit all "block node" usages to see if they need to become "visible block node", now that block nodes can be invisible (if they descend from display: none).
A block node is either an {{Element}} whose "display" property does not have resolved value "inline" or "inline-block" or "inline-table" or "none", or a [=document=], or a {{DocumentFragment}}.
An inline node is a node that is not a block node.
Something is editable if it is a node; it is not an [=editing host=]; it does not
have a
contenteditable attribute set to the false state; its
[=tree/parent=] is an [=editing host=] or editable; and either it is an HTML element, or it is an
svg or
math element, or it is not an {{Element}} and its
[=tree/parent=] is an HTML element.
An editable node cannot be a [=document=] or {{DocumentFragment}}, its [=tree/parent=] cannot be null, and it must descend from either an {{Element}} or a [=document=].
The editing host of node is null if node is neither editable nor an [=editing host=]; node itself, if node is an [=editing host=]; or the nearest [=tree/ancestor=] of node that is an [=editing host=], if node is editable.
Two nodes are in the same editing host if the editing host of the first is non-null and the same as the editing host of the second.
Barring bugs, the algorithms here will not alter the attributes of a non-editable element; will not remove a non-editable node from its parent (except to immediately give it a new parent in the same editing host); and will not add, remove, or reorder children of a node unless it is either editable or an editing host. An editing host is never editable, so authors are assured that editing commands will only modify the editing host's contents and not the editing host itself.
A collapsed line break is a [^br^] that begins a line box which has nothing else in it, and therefore has zero height.
Is this a good definition at all? I mean things like <p>foo<br></p>, or the second one in <p>foo<br><br></p>. The way I test it is by adding a text node after it containing a zwsp; if that changes the offsetHeight of its nearest non-inline ancestor, I deem it collapsed. But what if it happens to be display: none right now, for instance? Or its ancestor has a fixed height? Would it be better to use some DOM-based definition?
TODO: The thing about li is a not very nice hack. The issue is that an li won't collapse even if it has no children at all, but that's not true in all browsers (at least not in Opera 11.11), and also it breaks assumptions elsewhere. E.g., if it gets turned into a p.
An extraneous line break is a [^br^] that has no visual effect, in that removing it from the DOM would not change layout, except that a [^br^] that is the sole child of an [^li^] is not extraneous.
Also possibly a bad definition. Again, I test by just removing it and seeing what happens. (Actually, setting display: none, so that it doesn't mess up ranges.)
A whitespace node is either a {{Text}} node whose {{CharacterData/data}} is the empty string; or a {{Text}} node whose {{CharacterData/data}} consists only of one or more tabs (0x0009), line feeds (0x000A), carriage returns (0x000D), and/or spaces (0x0020), and whose [=tree/parent=] is an {{Element}} whose resolved value for "white-space" is "normal" or "nowrap"; or a {{Text}} node whose {{CharacterData/data}} consists only of one or more tabs (0x0009), carriage returns (0x000D), and/or spaces (0x0020), and whose [=tree/parent=] is an {{Element}} whose resolved value for "white-space" is "pre-line".
node is a collapsed whitespace node if the following algorithm returns true:
This definition is also bad. It's a crude attempt to emulate CSS2.1 16.6.1, but leaving out a ton of the subtleties. I actually don't want the exact CSS definitions, because those depend on things like where lines are broken, but I'm not sure this definition is right anyway. E.g., what about a pre-line text node consisting of a single line break that's at the end of a block? That collapses, same idea as an extraneous line break. We could also worry about nodes containing only zwsp or such if we wanted, or display: none, or . . .
At this point we know node consists of some whitespace, of a sort that will collapse if it's at the start or end of a line. We go backwards until we find the first block boundary, and if everything until there is invisible or whitespace, we conclude that node is collapsed. We assume a block boundary is either when we hit a line break or block node, or we hit the end of ancestor (which is the nearest ancestor block node). All this is very imprecise, of course, but it's fairly simple and will work in common cases.
We have to avoid invoking the definition of "visible" here to avoid infinite recursion: that depends on the concept of collapsed whitespace nodes. Instead, we repeat the parts we need, which turns out to be "not much of it".
Let reference be node.
We found something before our text node on (probably) the same line, so presumably it's not at the line's start. Now we need to look forward and see if we're at the line's end. If we aren't there either, then we assume we're not collapsed, so return false.
Let reference be node.
TODO: Consider whether we really want to depend on img specifically here. It seems more likely that we want something like "any replaced content that has nonzero height and width" or such. When fixing this, make sure to audit for other occurrences of this assumption.
Something is visible if it is a node that either is a block node, or a {{Text}} node that is not a collapsed whitespace node, or an [^img^], or a [^br^] that is not an extraneous line break, or any node with a visible [=tree/descendant=]; excluding any node with an [=tree/inclusive ancestor=] {{Element}} whose "display" property has resolved value "none".
Something is invisible if it is a node that is not visible.
TODO: Reconsider whether we want to lump invisible nodes in here. If we don't and change the definition, make sure to audit all callers, since then a block could have collapsed block prop descendants that aren't children.
A collapsed block prop is either a collapsed line break that is not an extraneous line break, or an {{Element}} that is an inline node and whose [=tree/children=] are all either invisible or collapsed block props and that has at least one [=tree/child=] that is a collapsed block prop.
A collapsed block prop is something like the <br> in <p><br></p>, or the <br> and <span> in
<p><span><br></span></p>. These
are necessary to stop the block from having zero height when it has no
other contents, but serve no purpose and should be removed once the
block has other contents that stop it from collapsing.
TODO: I say "first range" because I think that's what Gecko actually does, and Gecko is the only one that allows multiple ranges in a selection. This is keeping in mind that it stores ranges sorted by start, not by the order the user added them, and silently removes or shortens existing ranges to avoid overlap. It probably makes the most sense in the long term to have the command affect all ranges. But I'll leave this for later.
The active range is the [=range=] of the
selection
given by calling getSelection() on the context object. (Thus
the active range may be null.)
Each {{Document}} has a boolean CSS styling
flag associated with it, which must initially be false. (The styleWithCSS
command can be used to modify or query it, by means of the
execCommand() and
queryCommandState()
methods.)
Each {{Document}} is associated with a string known as the default single-line container
name, which must initially be "div". (The defaultParagraphSeparator command can be used to modify
or query it, by means of the execCommand() and queryCommandValue() methods.)
For some commands, each
{{Document}} must have a boolean state
override and/or a string value
override. These do not change the command's state or value, but change the way some algorithms behave, as
specified in those algorithms' definitions. Initially, both must be
unset for every command. Whenever the number of
[=ranges=] in the selection changes to something different, and
whenever a [=boundary point=] of the [=range=] at a given index in the
selection
changes to something different, the state
override and value override must be
unset for every command. The value override for the backColor
command must be the same as the value
override for the hiliteColor command, such that setting one sets the other
to the same thing and unsetting one unsets the other.
The primary purpose of state and value overrides is that if the user
runs a command like bold with a collapsed selection, then types something
without moving the cursor, they expect it to have the given style (bold
or such). Thus the commands like bold set state and value
overrides, and insertText checks for them and applies them to the
newly-inserted text. Other commands like delete also interact
with overrides.
See bug 16207.
When
document.open() is called and a [=document=]'s singleton
objects are all replaced by new instances of those objects, editing
state associated with that document (including the CSS styling flag, default single-line container
name, and any state overrides or value overrides) must be reset.
Of course, any action that replaces a [=document=] object entirely, such as reloading the page, will also reset any editing state associated with the document.
When this specification refers to a method or attribute that is defined in a specification, the user agent must treat the method or attribute as defined by that specification. In particular, if a script has overridden a standard property with a custom one, the user agent must only use the overridden property when a script refers to it, and must continue to use the specification-defined behavior when this specification refers to it.
When a list or set of nodes is assigned to a variable without specifying the order, they must be initially in [=tree order=], if they share a root. (If they don't share a root, the order will be specified.) When the user agent is instructed to run particular steps for each member of a list, it must do so sequentially in the list's order.
To move a node to a new location, preserving ranges, remove the node from its original [=tree/parent=] (if any), then insert it in the new location. In doing so, follow these rules instead of those defined by the [=insert=] and [=remove=] algorithms:
Many of the algorithms in this specification move nodes around in the
DOM. The normal rules for range mutation require that any range
endpoints inside those nodes are moved to the node's parent as soon
as the node is moved, which would corrupt the selection. For
instance, if the user selects the text "foo" and then bolds it, first
we produce <b></b>foo, then
<b>foo</b>. When we move the "foo"
text node into its new parent, we have to do so "preserving ranges",
so that the text "foo" is still selected.
This is actually implicit, but I state it anyway for completeness.
If a [=boundary point=]'s node is the same as or a [=tree/descendant=] of node, leave it unchanged, so it moves to the new location.
TODO: Do we want to get rid of attributes that are no longer allowed here?
To set the tag name of an {{Element}} element to new name:
This is needed because the DOM doesn't allow any way of changing an existing element's name. Sometimes we want to, e.g., convert a markup element to a span. In that case we invoke this algorithm to create a new element, move it to the right place, copy attributes from the old element, move the old element's children, and remove the old element.
createElement(new
name) on the {{Node/ownerDocument}} of element.
To remove extraneous line breaks before a node node:
<br> sometimes has no effect in CSS, such
as in the markup foo<br><p>bar</p>. In such cases we like
to remove the extra markup to keep things tidy.
To remove extraneous line breaks at the end of a node node:
To remove extraneous line breaks from a node, first remove extraneous line breaks before it, then remove extraneous line breaks at the end of it.
To wrap a list node list of consecutive [=tree/sibling=] nodes, run the following algorithm. In addition to node list, the algorithm accepts two inputs: an algorithm sibling criteria that accepts a node as input and outputs a boolean, and an algorithm new parent instructions that accepts nothing as input and outputs a node or null. If not provided, sibling criteria returns false and new parent instructions returns null.
This algorithm basically does two things. First, it looks at the
previous and next siblings of the nodes in node
list. If running sibling criteria on one or
both of the siblings returns true, the nodes in node
list are moved into the sibling(s). Otherwise, new parent instructions is run, and the result is used to
wrap node list. For instance, to wrap node list in a <b>, one might
invoke this algorithm with sibling criteria
returning true only for <b> elements and
new parent instructions creating and returning a
new <b> element.
We need to treat [^br^]s as visible here even if they're not, because wrapping them might be significant even if they're invisible: it can turn an extraneous line break into a non-extraneous one.
If every member of node list is invisible, and none is a [^br^], return null and abort these steps.
Trailing br's like this always need to go along with their line. Otherwise they'll create an extra line if we wrap in a block element, instead of vanishing as they should.
If node list's last member is an inline node that's not a [^br^], and node list's last member's {{Node/nextSibling}} is a [^br^], append that [^br^] to node list.
See bug
13811, bug
14231. If there's a non-adjacent sibling that matches the
sibling criteria and only invisible nodes intervene, we want to
skip over the invisible nodes. For instance, bolding <b>foo</b><!--bar-->[baz] should
produce <b>foo<!--bar-->baz</b>. Similarly,
and more usefully, creating an ordered list with <ol><li>foo</ol>
<p>[bar]</p> should produce <ol><li>foo</li>
<li>[bar]</ol>, not <ol><li>foo</ol>
<ol><li>[bar]</ol>.
While node list's first member's {{Node/previousSibling}} is invisible, prepend it to node list.
This can only happen if new parent instructions is run and it returns null. This can be used to only merge with adjacent siblings, in case you don't want to create a new parent if that fails.
If new parent is null, abort these steps and return null.
Most callers will create a new element to return in new parent instructions, whose parent will therefore be null. But they can also return an existing node if that makes sense, so the nodes will be moved to an uncle or something. The toggle lists algorithm makes use of this.
If new parent's [=tree/parent=] is null:
Basically, we want any boundary points around the wrapped nodes to go inside the wrapper. Without this step, wrapping "{}<br>" in a blockquote would go like
{}<br>
-> {}<blockquote></blockquote><br>
-> {}<blockquote><br></blockquote>.
The second line is due to range mutation rules: a boundary point with an offset equal to the index of a newly-inserted node stays put, so it remains before it. With this step, it goes like
{}<br>
-> {}<blockquote></blockquote><br>
-> <blockquote></blockquote>{}<br>
-> <blockquote>{}<br></blockquote>.
The difference in the final step is because we move the <br> "preserving ranges". This means that adjacent boundary points get swept along with it. Previously, the <blockquote> intervened, so a boundary point after it would get taken along but one before it would not.
Another solution that one might be tempted to consider would be to just put the wrapper after the wrapped elements. Then the boundary points would stay put, before the wrapper, so they'd still be adjacent to the nodes to be wrapped, like:
{<p>foo</p>}
-> {<p>foo</p>}<blockquote></blockquote>
-> <blockquote>{<p>foo</p>}</blockquote>.
The problem is that this completely breaks if you're wrapping multiple things and not all are selected. It would go like this:
<p>foo</p>{<p>bar</p>}
-> <p>foo</p>{<p>bar</p>}<blockquote></blockquote>
-> <p>foo</p><blockquote>{<p>bar</p>}</blockquote>
-> <blockquote>{<p>foo</p><p>bar</p>}</blockquote>.
The last step is again because of the range mutation rules: the boundary point stays put when a new node is inserted. They're fundamentally asymmetric.
An alternative solution would be to define the concept of moving a list of adjacent sibling nodes while preserving ranges, and handle this explicitly at a more abstract level.
TODO: Think about this some more. Maybe there's a better way.
If any [=range=] has a [=boundary point=] with node equal to the [=tree/parent=] of new parent and [=boundary point/offset=] equal to the [=tree/index=] of new parent, add one to that [=boundary point=]'s [=boundary point/offset=].
createElement("br")
on the {{Node/ ownerDocument}} of new
parent and append the result as the last [=tree/child=]
of new parent.
createElement("br")
on the {{Node/ ownerDocument}} of new
parent and insert the result as the first [=tree/child=]
of new parent.
This could happen if new parent instructions returned a node whose parent wasn't null.
If original parent is editable and has no [=tree/children=], remove it from its [=tree/parent=].
Probably because both the previous and next sibling met them. We want to merge them in this case.
If new parent's {{Node/nextSibling}} is editable and running sibling criteria on it returns true:
createElement("br")
on the {{Node/ ownerDocument}} of new parent
and append the result as the last [=tree/child=] of new parent.
List is mostly based on current HTML5, together with obsolete elements. I mostly got the obsolete element list by testing what Firefox 5.0a2 splits when you do insertHorizontalRule.
TODO: The definitions of prohibited paragraph children and elements with inline contents should be in the HTML spec (possibly under a different name) so they don't fall out of sync. They'll do for now.
A name of an element with inline contents is "a", "abbr", "b", "bdi", "bdo", "cite", "code", "dfn", "em", "h1", "h2", "h3", "h4", "h5", "h6", "i", "kbd", "mark", "p", "pre", "q", "rp", "rt", "ruby", "s", "samp", "small", "span", "strong", "sub", "sup", "u", "var", "acronym", "listing", "strike", "xmp", "big", "blink", "font", "marquee", "nobr", or "tt".
An element with inline contents is an HTML element whose [=Element/local name=] is a name of an element with inline contents.
TODO: This list doesn't currently match HTML's validity requirements for a few reasons:
I deliberately allow [^dt^] to contain headers and such, in violation of HTML. If I didn't, then when the user tried to formatBlock a [^dt^] as a header, it would break apart the whole [^dl^], which seems worse. See bug 13201.
A node or string child is an allowed child of a node or string parent if the following algorithm returns true:
Often we move around nodes, and sometimes this can result in
unreasonable things like two <p>'s nested
inside one another. This algorithm checks for DOMs we never want to
have, so that other algorithms can avoid creating them or fix them if
they do happen. The fix
disallowed ancestors algorithm is one frequently-invoked caller
of this algorithm.
Actually, no node can occur in the DOM after plaintext, generally. But let's not get too carried away.
If parent is "script", "style", "plaintext", or "xmp", or an HTML element with [=Element/local name=] equal to one of those, and child is not a {{Text}} node, return false.
Cannot be serialized as text/html. In some cases it can, like <a>foo<table><td><a>bar</a></td></table>baz</a>, but it's invalid in those cases too, so no need for complication.
If child is "a", and parent or some [=tree/ancestor=] of parent is an [^a^], return false.
This generally cannot be serialized either, for p. For other elements with inline contents, this serves to prevent things like <span><p>foo</p></span>, which will parse fine but aren't supposed to happen anyway.
If child is a prohibited paragraph child name and parent or some [=tree/ancestor=] of parent is an element with inline contents, return false.
Also can't be serialized as text/html.
If child is "h1", "h2", "h3", "h4", "h5", or "h6", and parent or some [=tree/ancestor=] of parent is an HTML element with [=Element/local name=] "h1", "h2", "h3", "h4", "h5", or "h6", return false.
Further requirements only care about the parent itself, not ancestors, so we don't need to know the node itself.
Let parent be the [=Element/local name=] of parent.
We allow children even where some intervening nodes will be inserted, like tr as a child of table.
If parent is on the left-hand side of an entry on the following list, then return true if child is listed on the right-hand side of that entry, and false otherwise.
dd/dt/li will serialize fine as the child of random stuff, but it makes no sense at all, so we want to avoid it anyway.
If child is "dd" or "dt" and parent is not "dl", return false.
The difference between "contained" and "effectively contained" is basically that 1) in <b>[foo]</b>, the text node and the <b> are effectively contained but not contained; and 2) in <b>f[o]o</b>, the text node is effectively contained but not contained, and the <b> is neither effectively contained nor contained.
A node node is effectively contained in a [=range=] range if range is not {{AbstractRange/collapsed}}, and at least one of the following holds:
So like <b>f[oo]</b> or <b>f[o]o</b> or <b>f[oo</b>}, but not <b>foo[</b>} or <b>f[]oo</b>.
node is range's [=range/start node=], it is a {{Text}} node, and its [=Node/length=] is different from range's [=range/start offset=].
Basically, anything whose children are all effectively contained should be effectively contained itself, except that in a case like <b>f[o]o</b> we don't want <b> to be effectively contained even though the text node is. That's because we split the text node before we actually do anything, and the <b> will no longer be effectively contained.
node has at least one [=tree/child=]; and all its [=tree/children=] are effectively contained in range; and either range's [=range/start node=] is not a [=tree/descendant=] of node or is not a {{Text}} node or range's [=range/start offset=] is zero; and either range's [=range/end node=] is not a [=tree/descendant=] of node or is not a {{Text}} node or range's [=range/end offset=] is its [=range/end node=]'s [=Node/length=].
A modifiable element is a [^b^],
[^em^], [^i^], [^s^], [^span^], [^strike^], [^strong^],
sub,
sup, or [^u^] element with no attributes except possibly
style; or a [^font^] element with no attributes except
possibly
style,
color,
face, and/or
size; or an [^a^] element with no attributes except
possibly
style and/or
href.
A simple modifiable element is an HTML element for which at least one of the following holds:
sub,
sup, or [^u^] element with no attributes.
sub,
sup, or [^u^] element with exactly one attribute, which
is
style, which sets no CSS properties (including invalid
or unrecognized properties).
href.
color,
face, or
size.
style, and the
style attribute sets exactly one CSS property (including
invalid or unrecognized properties), which is "font-weight".
style, and the
style attribute sets exactly one CSS property (including
invalid or unrecognized properties), which is "font-style".
style, and the
style attribute sets exactly one CSS property (including
invalid or unrecognized properties), and that property is not
"text-decoration".
style, and the
style attribute sets exactly one CSS property (including
invalid or unrecognized properties), which is "text-decoration",
which is set to "line-through" or "underline" or "overline" or
"none".
Conceptually, a simple modifiable element is a modifiable element
which specifies a value for at most one command. As the names imply,
inline formatting commands will try not to modify anything other than
modifiable elements. For instance, <dfn>
normally creates italics, but it's not modifiable, so running
the italic
command will not remove it: it will nest <span
style="font-style: normal"> inside.
A formattable node is an editable visible node that is either a {{Text}} node, an [^img^], or a [^br^].
Two quantities are equivalent values for a command if either both are null, or both are strings and they're equal and the command does not define any equivalent values, or both are strings and the command defines equivalent values and they match the definition.
Two quantities are loosely
equivalent values for a command if
either they are equivalent values
for the command, or if the command is the
fontSize command; one of the quantities is
one of "x-small", "small", "medium", "large", "x-large", "xx-large",
or "xxx-large"; and the other quantity is the resolved value of
"font-size" on a [^font^] element whose
size attribute has the corresponding value set ("1"
through "7" respectively).
Loose equivalence needs to be used when comparing effective command values to other values, while regular equivalence is used in other cases. The effective command value for fontSize is converted to pixels, so comparing it to a specified value literally would produce false negatives. But a specified value in pixels is actually different from a specified value like "small" or "x-large", because there is no precise mapping from such keywords to pixels.
If a command has inline command activated values defined but nothing else defines when it is indeterminate, it is indeterminate if among formattable nodes effectively contained in the active range, there is at least one whose effective command value is one of the given values and at least one whose effective command value is not one of the given values.
For bold and similar commands, IE 9 RC seems to consider the state true or false depending on the first element. All other browsers follow the same general idea as the spec, considering a range bold only if all text in it is bold, and this seems to match at least OpenOffice.org's bold feature. Opera 11.11 seemingly doesn't take CSS into account, and only looks at whether something descends from a <b>. I couldn't properly test IE9 because it threw exceptions (Error: Unspecified error.) on most of the tests I ran. But what I have here seems to match Firefox 6.0a2 in every case, and Chrome 14 dev in all cases with a few exceptions.
If a command has inline command activated values defined, its state is true if either no formattable node is effectively contained in the active range, and the active range's [=range/start node=]'s effective command value is one of the given values; or if there is at least one formattable node effectively contained in the active range, and all of them have an effective command value equal to one of the given values.
Testing with hiliteColor: Opera 11.11 seems to always return the effective command value of the active range's start node. Chrome 14 dev returns boolean false consistently, bizarrely enough. Firefox 6.0a2 seems to follow the same idea as the spec, but it likes to return "transparent", including sometimes when the answer really clearly should not be "transparent". IE9 throws exceptions most of the time for backColor, so I can't say for sure, but in the few cases where it doesn't throw it returns a random-looking number, so I'll assume it's crazy like for foreColor.
I decided on something that would guarantee the following invariant: whenever you execute a command with a value provided (assuming value is relevant), queryCommandValue() will always return something equivalent to what you set.
If a command is a standard inline value command, it is indeterminate if among formattable nodes that are effectively contained in the active range, there are two that have distinct effective command values. Its value is the effective command value of the first formattable node that is effectively contained in the active range; or if there is no such node, the effective command value of the active range's [=range/start node=]; or if that is null, the empty string.
The notions of inline command activated values and standard inline value commands are mostly just shorthand to avoid repeating the same boilerplate half a dozen times.
The effective command value of a node node for a given command is returned by the following algorithm, which will return either a string or null:
This is logically somewhat like CSS computed or resolved values, and
in fact for most commands it's identical to CSS resolved values (see
the end of the algorithm). We need a separate concept for some
commands where we can't rely on CSS for some reason: createLink and
unlink aren't CSS-related at all, backColor and hiliteColor need
special treatment because background-color isn't an inherited
property, subscript and superscript rely on <sub>/<sup> instead of
CSS vertical-align, and strikethrough and underline don't map to
unique CSS properties.
What happens if everything's background is fully transparent? See bug. If you do queryCommandValue() for backColor/hiliteColor when no backgrounds are set anywhere, so it goes up to the root element, no two engines agree. IE10PP2 just returns a random-looking number (16777215). Firefox 8.0a2 returns "transparent", Chrome 15 dev returns "rgba(0, 0, 0, 0)", and Opera 11.50 returns "rgb(255, 255, 255)".
Opera's behavior is incorrect. The current page might be an iframe, in which case the background really will be transparent and the (inaccessible) background color of the parent page will show through. Also, the user might have changed their preferences, but I'm not too worried about that.
So instead we just return the value as-is. This means that it will be fully transparent, which is perhaps somewhat useless information, but it's the best we can do. More generally, any non-opaque value is not going to tell you what you actually want, namely "what color is the user actually seeing?" We have no realistic way to work around this in the general case.
Return the resolved value of "background-color" for node.
Firefox 6.0a2 ignores vertical-align for this purpose, and only cares about <sub> and <sup> tags themselves. Opera 11.11 is similar, and in fact behaves like that even for commands like bold. The spec originally followed Chrome 14 dev, mainly because WebKit itself will produce spans with vertical-align sub or super, and we want to handle them correctly. However, Ryosuke informs me that WebKit's behavior here is viewed as a bug, so I changed it to match Gecko/Opera.
If node is a
sub, set affected by
subscript to true.
sup, set affected by
superscript to true.
The specified command value of an {{Element}} element for a given command is returned by the following algorithm, which will return either a string or null:
This is logically somewhat like CSS inline style. In addition to the
caveats for effective command value, we also treat elements like
<b> and <font> as having the same meaning as <span>s with inline style set, because they're
logically pretty much the same and can in fact be produced by the
same command depending on the CSS styling
flag.
href attribute, return the [=Attr/value=] of that
attribute.
style attribute set, and that attribute sets
"text-decoration":
style attribute sets "text-decoration" to a value
containing "line-through", return "line-through".
style attribute set, and that attribute sets
"text-decoration":
style attribute sets "text-decoration" to a value
containing "underline", return "underline".
style attribute set, and that attribute has the effect
of setting property, return the value that it
sets property to.
size of 7, this will be the non-CSS value "xxx-large".)
To record the values of a list of nodes node list:
When we move nodes around, we often change their parents. If their
parents had any styles applied, this will make the nodes' styles
change too, which often isn't what we want. For instance, if
something is wrapped in <blockquote style="color:
red">, and a script runs the
outdent command on it, the blockquote will
be removed and the style will go along with it. Recording the values
of its children first, then restoring them afterward, will ensure the
nodes don't change color when outdented.
As with removeFormat, we put subscript first so it doesn't interfere with fontSize, and omit superscript because it's redundant with subscript.
For each node in node list, for each command in the list "subscript", "bold", "fontName", "fontSize", "foreColor", "hiliteColor", "italic", "strikethrough", and "underline" in that order:
To restore the values specified by a list values returned by the record the values algorithm:
To clear the value of an {{Element}} element:
The idea is to remove any specified command value that the element might have for the command. This might involve changing its attributes, setting its tag name, or removing it entirely while leaving its children in place. The key caller is set the selection's value, which clears the values of everything in the selection before doing anything else to keep the markup tidy.
We want to abort early so that we don't try unsetting background-color on a non-inline element.
If element's specified command value for command is null, return the empty list.
style attribute that sets "text-decoration" to some
value containing "line-through", delete "line-through" from the
value.
style attribute that sets "text-decoration" to some
value containing "underline", delete "underline" from the value.
href property of element.
If we get past this step, we're something like <b class=foo> where we want to keep the extra attributes, so we stick them on a span.
If element's specified command value for command is null, return the empty list.
This algorithm goes up to just below the nearest ancestor with the right style, then re-applies the bad styles repeatedly going down, omitting the things we want to have the new style. This is basically what WebKit does, although WebKit sometimes starts higher up and therefore makes more intrusive changes, often creating more markup. IE follows the same general approach too.
Gecko instead seems to start breaking up elements from the bottom, so that the range consists of a few consecutive siblings, and it can then break up the problematic element into a maximum of two pieces. The spec's approach seems to create fewer elements and simpler markup (or at least markup that's no more complex) in most cases I throw at it.
Gecko's approach does have the major advantage that it gets underlines right in many cases for free. E.g.,
<u>foo<font color=red>[bar]baz</font></u> -> <u>foo</u><font color=red>bar<u>baz</u></font> (spec) -> <u>foo</u><font color=red>bar</font><u><font color=red>baz</font></u> (Gecko)
The spec's markup here is much shorter and contains fewer elements, but is wrong: the underline under "baz" has changed color from black to red. It might be worth trying to copy Gecko's results in such cases, but that won't solve all underline problems, so perhaps it's not worth it.
Opera also seems to break up the markup surrounding the range, but even more aggressively: even if it doesn't need to pull down styles. In some cases this does actually result in shorter markup, specifically if the existing tags are short (like i or b) and we're adding tags that are long (like span with a style attribute).
To push down values to a node node, given a new value new value:
The idea here is that if an undesired value is being propagated from an ancestor, we remove that style from the ancestor and re-apply it to all the descendants other than node. This way we don't have to have nested styles, which is usually more cluttered (although not always).
E.g., a text node child of a document fragment.
If node's [=tree/parent=] is not an {{Element}}, abort this algorithm.
We can only remove specified values, so if the value isn't specified, give up. Unless we're actually trying to push down a null specified value, like for unlink.
If propagated value is null and is not equal to new value, abort this algorithm.
If we go all the way up to the root and still don't have the desired value, pushing down values is pointless. It will create extra markup for no purpose. Except if the value is null, which basically just means "try to get rid of anything affecting the current element but don't aim for any specific value".
Nevertheless, Chrome 14 dev does seem to do this. Running bold on <span style=font-weight:300>f[o]o</span> breaks up the span and adds a <b> as a sibling. In IE9, Firefox 6.0a2, and Opera 11.50, it instead nests the <b> inside the <span>. It's a tradeoff: WebKit's behavior is better for things like
<font color=red>fo[o</font><font color=blue>b]ar</font> -> <font color=red>fo</font><font color=green>[ob]</font><font color=blue>ar</font>
(where the spec adds two extra font tags instead of one), but the spec is simpler for things like
<font color=red>f[o]o</font> -> <font color=red>f<font color=green>[o]</font>o</font>
(where WebKit splits the existing tag up in addition to creating a new tag). I'm not particularly sure which approach is better overall, so I'll go with the majority of browsers. If these algorithms move to use runs of consecutive siblings instead of doing everything node-by-node, it might make sense to break up the parent as long as it won't create an extra node (i.e., we're styling something that includes the first or last child).
If the effective command value of command is not loosely equivalent to new value on the [=tree/parent=] of the last member of ancestor list, and new value is not null, abort this algorithm.
TODO: This will be incorrect for relative font sizes. If the font size on the parent was removed and the font size on the child is in ems or percents or something, it will now change value. This isn't likely to come up, so we'll ignore it for now.
If child is an {{Element}} whose specified command value for command is neither null nor equivalent to propagated value, continue with the next child.
To force the value of a node node to new value:
This algorithm checks if the node has the desired value, and if not, it wraps the node (or, if that's not possible, its descendants) in a simple modifiable element. After forcing the value, descendants might still have a different value.
Even if the value matches, we stick it in a preceding sibling if possible. This ensures "a<cite>b</cite>c" -> "<i>a<cite>b</cite>c</i>" instead of "<i>a</i><cite>b</cite><i>c</i>". While we're at it, we also handle more elaborate cases like <b>foo</b>[bar]<b>baz</b> and even <i><b>foo</b></i>[bar]<i><b>baz</b></i> (the latter becomes <b><i>foo</i>bar<i>baz</i></b>).
Theoretically this algorithm could pointlessly reorganize the DOM in the event of unreasonable style rules, but it's not a big enough deal for us to care, since the resulting style will still be right.
Reorder modifiable descendants of node's {{Node/ previousSibling}}.
The new parent instructions we'd want are too complicated to reasonably feed into the wrap algorithm, so we just let them return null and do the wrapping ourselves if sibling criteria didn't return true.
Wrap the one-node list consisting of node, with sibling criteria returning true for a simple modifiable element whose specified command value is equivalent to new value and whose effective command value is loosely equivalent to new value and false otherwise, and with new parent instructions returning null.
If node is invisible, abort this algorithm.
This means that if it has no children, we do nothing. IE9 inserts an empty wrapper element in that case, but I'm not sure what the point is, and no one else does, so I don't. WebKit seems to ignore the node if its only child consists solely of whitespace, but I don't see any grounds for that and no one else does, so I don't.
Force the value of each node in children, with command and new value as in this invocation of the algorithm.
createElement("b")
on the {{Node/ownerDocument}} of node.
createElement("i")
on the {{Node/ownerDocument}} of node.
TODO: Actual UAs use strike, not s, but s is shorter and HTML5 makes strike invalid. I've gone with s for now, but maybe we want to change the spec to require strike.
If command is "strikethrough" and
new value is "line-through", let
new parent be the result of calling
createElement("s")
on the {{Node/ ownerDocument}} of node.
createElement("u")
on the {{Node/ownerDocument}} of node.
See comment for foreColor for discussion. TODO: Define more carefully what happens when things are out of range or not integers or whatever.
If command is "foreColor", and new value is fully opaque with red, green, and blue components in the range 0 to 255:
createElement("font")
on the {{Node/ ownerDocument}} of node.
color attribute of new
parent to the result of applying the
rules for serializing simple color values to
new value (interpreted as a
simple color).
createElement("font")
on the {{Node/ownerDocument}} of node, then
set the
face attribute of new parent to
new value.
createElement("a")
on the {{Node/ownerDocument}} of node.
href attribute of new parent to
new value.
Nested a elements are bad, because they can't be serialized to text/html. hrefs should already have been cleared in a previous step, but we might have <a name> or such lurking about.
Let ancestor be node's [=tree/parent=].
TODO: This will mean any link-specific attributes will be transferred, which makes them both invalid and useless. Is that okay? I don't really want to list them all, because that sort of list is prone to bitrot.
If ancestor is an [^a^], set the tag name of ancestor to "span", and let ancestor be the result.
WebKit is the only engine that ever outputs anything but font tags for fontSize. For size=7, it uses font-size: -webkit-xxx-large. We just output a font tag no matter what for size=7.
If command is "fontSize"; and new value is one of "x-small", "small", "medium",
"large", "x-large", "xx-large", or "xxx-large"; and either the
CSS styling flag is false, or
new value is "xxx-large": let new parent be the result of calling createElement("font")
on the {{Node/ownerDocument}} of node, then
set the
size attribute of new parent to
the number from the following table based on new
value:
We always use sup/sub elements, even in CSS mode, following Gecko and contradicting WebKit. This is because <span value="vertical-align: sub/super">, the obvious equivalent (and what WebKit uses), behaves quite differently: it doesn't reduce font-size, which is ugly. WebKit's behavior is a bug anyway.
If command is "subscript" or "superscript"
and new value is "subscript", let new parent be the result of calling createElement("sub")
on the {{Node/ownerDocument}} of node.
createElement("sup")
on the {{Node/ownerDocument}} of node.
createElement("span")
on the {{Node/ownerDocument}} of node.
This preserves boundary points correctly, as usual.
Insert new parent in node's [=tree/parent=] before node.
Need to be explicit. I think "if the new value would be valid" means "if the new value isn't xxx-large for font-size", need to double-check.
To reorder modifiable descendants of a node node, given a command command and a value new value:
If candidate had no children, any boundary point inside it will get moved to its parent here, which is okay. We don't want to preserve ranges, because that would move boundary points that originally were in candidate but were moved to its parent by the last step to move to node's parent.
We move to after node so that boundary points before and after node wind up consistently inside candidate when we move preserving ranges. If we had
{<node>foo<candidate></candidate></node>}
it thus becomes
{<node>foo</node>}<candidate></candidate>
by the range mutation rules, and then when we move preserving ranges, it becomes
<candidate>{<node>foo</node>}</candidate>
which is reasonable.
If we had inserted candidate before node, instead it would go
{<candidate></candidate><node>foo</node>}
{<candidate><node>foo</node>}</candidate>
because of the interaction of regular range mutation rules with preserving-ranges rules.
Insert candidate into node's [=tree/parent=] immediately after node.
To set the selection's value to new value:
The effect of this algorithm is to ensure that all nodes effectively contained in the selection have the value requested, producing the simplest markup possible to achieve that effect. It's inspired by the approach WebKit takes. The only places where the algorithm should fail are when there's an !important CSS rule that conflicts with the requested style (which we don't try to override because we assume it's !important for a reason), or when it's literally impossible to succeed (such as when a text-decoration or link URL is propagated from a non-editable ancestor). Any other failures are bugs.
First, if a node has a specified command value for the command, we unset it (clear its value). This step also removes simple modifiable elements entirely, and replaces elements like [^b^] or [^font^] with [^span^]s if they aren't simple modifiable elements. This will be sufficient if the desired value is inherited from an ancestor, or if it's the default (like font-style: normal) and no conflicting value is inherited from an ancestor. Even if clearing values doesn't actually fix the style of the node we're dealing with, we do it anyway to simplify the generated markup.
If clearing values didn't work, and it looks like an ancestor has a specified command value that we're inheriting, we push the value down from that ancestor. Thus if we're unbolding the letter "r" in
foo bar baz,
we get
foo bar baz.
If we didn't push down values, the final step (forcing values) would instead give us
foo bar baz,
which is much longer and uglier. We take care not to disturb the style or semantics of anything but the node we're dealing with.
We'll only push down values if some ancestor actually has the value we want, so we can inherit it. Otherwise, it will just create useless markup.
Finally, if neither of the above strategies worked, we have to add new markup to get the desired value (forcing the value). First we try just sticking it into its previous or next sibling, if that's a simple modifiable element (so it won't add any styles or semantics we don't want). Otherwise, we create a new simple modifiable element and wrap it in that. It's common that a previous sibling is the simple modifiable element we want, because often we'll set the value of several consecutive siblings in succession. In that case, the element created for the first can be reused for the later ones.
This last step works a bit differently if the node isn't an allowed child of "span". In that case, wrapping it in a simple modifiable element would make the document less conforming than it already was, or would cause other problems. Instead, we recursively force the value of its children. The recursion will terminate when we hit a node that's an allowed child of "span", or when there are no further descendants. (In the latter case, there are no descendants that are text nodes or such, so we don't really need to style anything.)
After all this, the node is guaranteed to have the value we want, barring bugs in the algorithm or the two exceptions noted earlier (!important style rules, and impossible cases). We then re-run the algorithm on each child recursively. Typically this means just clearing the value of each descendant, because it should then inherit the value we just set on its ancestor. In the unusual case that a descendant's value is wrong even after we clear its value, such as because of a non-inline style rule (like trying to unbold a heading), we'll repeat the above steps to ensure that the value really gets set as desired.
IE9 seems to wrap the whole line instead, or something like that, although it does nothing for createLink. We follow all other browsers' general behavior: change the state/value, and then make sure that takes effect if the user types something before changing the cursor position.
If there is no formattable node effectively contained in the active range:
The last sentence here just prettifies the resulting range a bit.
If the active range's [=range/start
node=] is an editable {{Text}} node, and
its [=range/start offset=] is neither zero nor its [=range/start
node=]'s [=Node/length=], call splitText()
on the active range's [=range/start
node=], with argument equal to the active
range's [=range/start offset=]. Then set the active range's [=range/start node=] to the
result, and its [=range/start offset=] to zero.
splitText()
on the active range's [=range/end node=],
with argument equal to the active range's
[=range/end offset=].
We skip non-editable nodes.
I chose to go with the non-IE behavior, per discussion. Ignoring non-editable things is convenient for the common use-case of an editor, where you don't want the user to bold random parts of the UI when they hit the bold button. For cases where it's not desired, you can always turn designMode on briefly before using execCommand(), so the non-IE behavior is a lot easier to work around than the IE behavior.
I don't see the value in ever just ignoring execCommand(). If the start and end are not editable, I'm going to say you should still style any editable nodes in between. I'm also going to ignore non-editable nodes for the purposes of determining state, so (for instance) if all the editable nodes are bolded, it will unbold instead of bolding.
Let node list be all editable nodes effectively contained in the active range.
TODO: This is inefficient. It would be most efficient to only push down values on the highest-level effectively contained nodes, and to batch operations so we handle runs of adjacent siblings at once. Should we bother fixing this?
For each node in node list:
If the node isn't an allowed child of "span", forcing its value will just force its children's value, which is redundant. So don't.
If node is an allowed child of "span", force the value of node.
backColor command
This command must not be enabled if the editing host is in the plaintext-only state.
For historical reasons, backColor and hiliteColor behave identically.
We have three behaviors to choose from for this one:
(1) is obviously redundant, but has plurality support, so we could spec it that way if the other ways were useless.
(3) is incoherent from a user perspective. For instance, if you try it on paragraphs the background will have big gaps where the margins are. If you try it on an inline element that's a child of the editing host, it will do nothing or apply the background to everything or such, even though such an inline element is visually indistinguishable from one sitting inside a div. This would only make sense if we take considerable effort to ensure that block elements all have no margins, or if we wrap things in a div if they have margins, or something like that.
That leaves (2). That might be useful if it actually set the document's background color, but it seems like it sets table cell backgrounds sometimes instead, which is really confusing.
The path of least resistance is to standardize this as meaning the same thing as hiliteColor, and make up new commands if we want to do things like set the document background color. See hiliteColor for comments.
Relevant CSS property: "background-color"
Equivalent values: Either both strings are valid CSS colors and have the same red, green, blue, and alpha components, or neither string is a valid CSS color.
bold command
This command must not be enabled if the editing host is in the plaintext-only state.
If the selection is collapsed (but not if it contains nothing but is not collapsed), IE9 wraps the whole line in a <strong>. This seems bizarre and no one else does it, so I don't do it. It's a similar story for similar commands (fontName, italic, etc.). Except not for strikethrough, where it just does nothing if the selection is empty. Why strikethrough? I don't know.
Action: If queryCommandState("bold") returns
true, set the selection's
value to "normal". Otherwise set the selection's value to "bold".
Either way, return true.
The cutoff of 600 matches Chrome 14 dev. The cutoff used by IE9 and Firefox 6.0a2 seems to be 500, and the distinction isn't relevant for Opera 11.11 (it doesn't use CSS here at all AFAICT). On my test systems with default fonts, Chrome 14 dev displays 700 and up as bold, while the other three display 600 and up as bold.
Thus in Chrome on my system, the bold command will behave a bit oddly the first time you hit it if there's anything in the range with font-weight: 600, but it will look right in other browsers. On the other hand, if I followed IE/Firefox, it would look wrong on all my browsers for font-weight: 500.
700 actually makes more sense: then you'd view 100-300 as light, 400-600 as medium, 700-900 as bold. But that's not how it seems to work in browsers, so I'll go with 600 as the cutoff.
Inline command activated values: "bold", "600", "700", "800", or "900"
Relevant CSS property: "font-weight"
Equivalent values: Either the two strings are equal, or one is "bold" and the other is "700", or one is "normal" and the other is "400".
createLink command
This command must not be enabled if the editing host is in the plaintext-only state.
If the selection doesn't contain anything (meaning, e.g., deleteContents() doesn't change anything), then Chrome 12 dev inserts a link at the selection start, with the text equal to the link URL. Other browsers don't do it, so I don't either.
IE10PP2, Firefox 7.0a2, Chrome 14 dev, and Opera 11.50 all do not support indeterminate, state, or value for createLink or unlink. I previously defined indeterminate and value anyway because they make sense, but then undefined them. The nontrivial thing is what value to return if there's no link, since any string can occur as a link href, in principle.
What are the use-cases for indeterm, state, or value for createLink/unlink?
Firefox 4b11 and Chrome 11 dev both silently do nothing in this case. IE 9 RC and Opera 11 both treat the request literally. Gecko and WebKit probably have it right here: users who enter no URL are very unlikely to want to link to a relative URL resolving to the current document. If they really want to, they can always specify "#" for the value, or the author can rewrite it, so it's not like this makes the API less useful.
If value is the empty string, return false.
There are three approaches here. For instance, if you ask browsers to create a link to "http://example.org" on the "b" here:
<a href=http://example.com><b>Abc</b></a>
Chrome 10 dev produces:
<b><a href=http://example.com>A</a><a href=http://example.org>b</a><a href=http://example.com>c</a></b>
Firefox 4b11 produces (roughly):
<a href=http://example.com><b>A<a href=http://example.org>b</a>c</b></a>
(This doesn't round-trip through text/html serialization.) IE 9 RC and Opera 11 produce simply:
<a href=http://example.org><b>Abc</b></a>
The last behavior probably best matches user expectations. If you happen to miss out a character when selecting the link you want to change, do you really intend to only change the link of part of it?
For each editable [^a^] element that has
an
href attribute and is an [=tree/ancestor=] of some
node effectively contained in the
active range, set that [^a^]
element's
href attribute to value.
fontName command
This command must not be enabled if the editing host is in the plaintext-only state.
UAs differ a bit in the details here:
Setting an empty font-family has the effect of inheriting the font from the parent (although I don't see where the February 24, 2011 CSS 3 Fonts draft says that). Thus it makes sense that if we special-case this, it should be to unset the font somehow.
Special-casing the empty string to do nothing doesn't make sense to me. With createLink we'd expect the user to enter the URL themselves, so it makes sense to special-case clicking OK without entering anything. But here it's very likely that the font list will be fixed by the author (how many users will understand CSS font-family syntax?), so I don't think such usability concerns apply.
Action: Set the selection's value to value, then return true.
The value is complicated.
I'm just going to punt on this and say it should be the resolved value of font-family. I'll leave CSSOM to decide what that means if there are no applicable style rules.
Relevant CSS property: "font-family"
fontSize command
This command must not be enabled if the editing host is in the plaintext-only state.
What all of these have in common is that they force the author to
deal with legacy font values and don't let them use CSS. This is
undesirable, but to avoid it we'd really have to create a new
command. If nothing else, the value returned by queryCommandValue() has to be numeric, so authors can't
really use the command sanely no matter what we do. See bug
14251.
Note that 1 is the same size as x-small in browsers, not xx-small, contrary to the CSS Fonts spec.
The entry for 7 here is an issue: there's no CSS value that corresponds to it. Even if we got one added to the drafts, it wouldn't be backward-compatible to use it. WebKit is the only engine that supports CSS output for fontSize, and it uses -webkit-xxx-large in this case, which is unworkable. Instead, we just always output a font tag for size 7. If authors want conforming markup, they'll need to give CSS sizes above size 7, not legacy sizes.
This follows Firefox 6.0a2. Chrome 14 dev always returns false. Note that indeterminacy here keys off the effective command value, while the value is based only on an approximation (a number from one to seven). Thus it's possible for every subrange of the selection to have the same value, but for the selection to still be indeterminate. Setting the fontSize to the value will make it determinate without changing anything's value.
Indeterminate: True if among formattable nodes that are effectively contained in the active range, there are two that have distinct effective command values. Otherwise false.
Chrome's behavior seems the most useful. As usual, IE returns a variable type and all other browsers return strings, and we follow other browsers.
If the selection isn't someplace editable, Chrome works like usual; some other browsers behave differently. I see no reason to behave differently.
See comment for standard inline value commands on how I decided on this choice of node.
Let pixel size be the effective command value of the first formattable node that is effectively contained in the active range, or if there is no such node, the effective command value of the active range's [=range/start node=], in either case interpreted as a number of pixels.
Relevant CSS property: "font-size"
The legacy font size for an integer pixel size is returned by the following algorithm:
size attribute is set to returned
size.
size attribute is set to one plus returned size.
foreColor command
This command must not be enabled if the editing host is in the plaintext-only state.
Color interpretations:
IE10PP2 Firefox 7.0a2 Chrome 14 dev Opera 11.50
blue blue blue #0000ff #0000ff
f #f - - #f00000
#f #f - - #f00000
00f #00f - #0000ff #00000f
#00f #00f rgb(0, 0, 255) #0000ff #00000f
0000ff #0000ff - #0000ff #0000ff
#0000ff #0000ff rgb(0, 0, 255) #0000ff #0000ff
000000fff #0000ff - - -
#000000fff #0000ff - - -
rgb(0, 0, 255) rgb(0,0,255) rgb(0, 0, 255) #0000ff #00b000
rgb(0%, 0%, 100%) rgb(0,0,255) rgb(0, 0, 255) #0000ff #00b000
rgb( 0 ,0 ,255) rgb(0,0,255) rgb(0, 0, 255) #0000ff #00b000
rgba(0, 0, 255, 0.0) #ba0000 rgba(0, 0, 255, 0) rgba(0, 0, 255, 0) #00ba00
rgb(15, -10, 375) rgb(15,0,255) rgb(15, 0, 255) #0f00ff #00b015
rgba(0, 0, 0, 1) #ba0010 rgb(0, 0, 0) - #00ba00
rgba(255, 255, 255, 1) #000055 rgb(255, 255, 255) #ffffff #00ba02
rgba(0, 0, 255, 0.5) #ba0000 rgba(0, 0, 255, 0.5) rgba(0, 0, 255, 0.5) #00ba00
hsl(240, 100%, 50%) #000150 rgb(0, 0, 255) #0000ff #000024
cornsilk cornsilk cornsilk #fff8dc #fff8dc
potato quiche #0000c0 - - #000a00
transparent transparent - rgba(0, 0, 0, 0) #00a000
currentColor #c0e000 currentcolor rgba(0, 0, 0, 0) #c000e0
The interpretations given for Firefox are only in styleWithCSS mode. In non-styleWithCSS mode, it just outputs the string literally as the <font color> attribute value, which can lead to different results. The given output for Chrome is for <font>; the output in styleWithCSS mode is the same, but rgb() is used instead of hex notation, and "transparent" and "currentcolor" are passed through under those names. IE and Opera only support <font> to begin with.
Conclusions:
What I'm going to say is that it either has to be a valid CSS
color, or prefixing it with # must result in a valid CSS color. For
<font>, I'll say that the output color
should be normalized to #xxxxxx form. If the color is not a simple
color (fully opaque with all channels between 0 and 255), I'll
force style="" even if styleWithCSS mode is
off. Some of this disagrees with all browsers, but it's unlikely to
hurt and it makes sense.
TODO: Define "valid CSS color" (here and in other color places).
If value is not a valid CSS color, prepend "#" to it.
currentColor is bad for the same reason as relative font sizes. It will confuse the algorithm, and doesn't seem very useful anyway.
If value is still not a valid CSS color, or if it is currentColor, return false.
Opera 11 seems to return true for the state if there's some color style applied, false otherwise, which seems fairly useless; authors want to use value here, not state. So I'll match other browsers and not define any state.
For value, the spec essentially matches Firefox 6.0a2 and Chrome 14 dev, as far as how to decide what color the node has. IE9 seems to always return the number 0 for some bizarre reason. There are some cases where Firefox returns the empty string for some reason, and it seems to select the active node a little differently. Opera uses #xxxxxx format for getComputedStyle() but rgb() here, and also drops the transparent part of the color if there is any.
Relevant CSS property: "color"
Equivalent values: Either both strings are valid CSS colors and have the same red, green, blue, and alpha components, or neither string is a valid CSS color.
hiliteColor command
This command must not be enabled if the editing host is in the plaintext-only state.
For historical reasons, backColor and hiliteColor behave identically.
IE 9 RC doesn't support this. It uses backColor instead, but Gecko and Opera treat that differently, while all non-IE browsers treat hiliteColor the same, so I'm standardizing hiliteColor as the way to highlight text.
This is slightly tricky, because background-color does different things on block and inline elements. Given the name ("hiliteColor"), we really only want to apply it to inline elements. This is how everyone but Gecko behaves, but Gecko sometimes applies it to blocks too. WebKit doesn't set it on non-inline elements, but does clear it and push it down from them.
The spec doesn't do any of these: background-color on non-inline elements is not touched by hiliteColor, neither created nor removed. If users want to remove the style, they need to use removeFormat. Adding it usually makes no sense; see the comment for backColor.
For color parsing, see the comment for foreColor.
See bug 13829.
currentColor is bad for the same reason as relative font sizes. It will confuse the algorithm, and doesn't seem very useful anyway. For hiliteColor you could conceive of it being useful, but it will still confuse the algorithm, so ban it for now anyway.
If value is still not a valid CSS color, or if it is currentColor, return false.
For indeterminacy, this follows no one. Firefox 6.0a2 and Chrome 14 dev both always return false. However, the spec makes sense, since it's consistent with other commands.
Relevant CSS property: "background-color"
Equivalent values: Either both strings are valid CSS colors and have the same red, green, blue, and alpha components, or neither string is a valid CSS color.
italic command
This command must not be enabled if the editing host is in the plaintext-only state.
Action: If queryCommandState("italic") returns
true, set the selection's
value to "normal". Otherwise set the selection's value to
"italic". Either way, return true.
Inline command activated values: "italic" or "oblique"
Relevant CSS property: "font-style"
removeFormat command
This command must not be enabled if the editing host is in the plaintext-only state.
See bug, and also research by Ryosuke for WebKit.
Tested in IE 9, Firefox 4.0, Chrome 12 dev, Opera 11.00.
All elements whose default rendering is display: block are left untouched by all browsers (although IE seems to throw an exception on <marquee> for some reason).
It's not clear to me why we should leave <a> alone, but everyone but Opera does. In OpenOffice.org 3.2.1, doing "Default Formatting (Ctrl+M)" doesn't remove links. In Microsoft Word 2007, doing "Clear Formatting" also doesn't remove links. Verdict: don't remove links. Apparently they don't logically qualify as "formatting".
Conclusion: IE/WebKit is a solid majority by market share and they're closely interoperable, since WebKit copied IE here. Also, it makes more sense to assume that unrecognized elements don't represent any kind of inline formatting, i.e., have a blacklist of elements to remove instead of a whitelist to keep. Thus I remove more or less the same things as IE/WebKit.
I remove blink because IE does it and it makes sense, although
Chrome doesn't; I remove abbr although only Firefox does, for
consistency with acronym; and I remove bdi and mark because they're
evidently left alone only because they're unrecognized. Finally, I
remove span because otherwise, something like <span style="font-variant: small-caps"> will be
left intact, which isn't expected and matches no browser except IE.
(Chrome doesn't remove spans in general, but it does remove spans
with style attributes, or something like that.)
Browsers will split up all these inline elements if the selection is contained within them. Opera does strip unrecognized elements with display: block if they're within the selection, but doesn't split them up if they contain the selection.
Chrome 14 dev removes style attributes from every element in the range, but IE10PP2, Firefox 7.0a2, and Opera 11.50 do not, so I go with them. As noted above, this means I need to remove spans. I could conceivably change to remove only spans with style attributes, but it doesn't seem worth it: I'll just match Gecko.
TODO: This has to be kept in sync when new HTML elements are added. I need to figure out some way of coordinating this.
A removeFormat candidate is an editable HTML element with [=Element/local name=] "abbr", "acronym", "b", "bdi", "bdo", "big", "blink", "cite", "code", "dfn", "em", "font", "i", "ins", "kbd", "mark", "nobr", "q", "s", "samp", "small", "span", "strike", "strong", "sub", "sup", "tt", "u", or "var".
The last sentence just prettifies the resulting range a bit.
If the active range's [=range/start
node=] is an editable {{Text}} node, and
its [=range/start offset=] is neither zero nor its [=range/start
node=]'s [=Node/length=], call splitText()
on the active range's [=range/start
node=], with argument equal to the active
range's [=range/start offset=]. Then set the active range's [=range/start node=] to the
result, and its [=range/start offset=] to zero.
splitText()
on the active range's [=range/end node=],
with argument equal to the active range's
[=range/end offset=].
TODO: Splitting the parent is really a block algorithm. It's not clear whether it's desirable to use for inline nodes. Perhaps it's okay, but it makes me a little uneasy.
For each node in node list, while node's [=tree/parent=] is a removeFormat candidate in the same editing host as node, split the parent of the one-node list consisting of node.
This step is for cases like <p style=font-weight:bold>foo[bar]baz</p>, where splitting/removing tags won't help. We don't need to run superscript, since subscript does the same thing here. We run subscript first so <sub>/<sup> won't upset fontSize.
For each of the entries in the following list, in the given order, set the selection's value to null, with command as given.
strikethrough command
This command must not be enabled if the editing host is in the plaintext-only state.
TODO: See underline TODO.
Action: If queryCommandState("strikethrough")
returns true, set the
selection's value to null. Otherwise set the selection's value to
"line-through". Either way, return true.
Inline command activated values: "line-through"
subscript command
This command must not be enabled if the editing host is in the plaintext-only state.
queryCommandState("subscript"), and
let state be the result.
Indeterminate: True if either among formattable nodes that are effectively contained in the active range, there is at least one with effective command value "subscript" and at least one with some other effective command value; or if there is some formattable node effectively contained in the active range with effective command value "mixed". Otherwise false.
For <sup><sub>foo</sub></sup>, Firefox 6.0a2 and Opera 11.11 say the state is true for both superscript and subscript, and indeterminate is false; Chrome 14 dev says it's true for subscript but not superscript, and indeterminate is false. We follow neither of these behaviors: we return false for both states, and say indeterminate is true. The reason is because we want to return true for a state if we'll do nothing, false if we'll do something; and if we have nesting like this, we'll always do something, namely get rid of all those ancestors and replace them with a single tag. This matches what happens in other indeterminate situations, so it's fair to consider it indeterminate.
Inline command activated values: "subscript"
superscript command
This command must not be enabled if the editing host is in the plaintext-only state.
queryCommandState("superscript"),
and let state be the result.
Indeterminate: True if either among formattable nodes that are effectively contained in the active range, there is at least one with effective command value "superscript" and at least one with some other effective command value; or if there is some formattable node effectively contained in the active range with effective command value "mixed". Otherwise false.
Inline command activated values: "superscript"
underline command
This command must not be enabled if the editing host is in the plaintext-only state.
TODO: There are a lot of problems with underline color and thickness, because text-decoration in CSS is horrible. These aren't prohibitive for normal use and existing browsers don't handle them either, so fixing these problems or working around them can be put off for now.
Action: If queryCommandState("underline")
returns true, set the
selection's value to null. Otherwise set the selection's value to
"underline". Either way, return true.
Inline command activated values: "underline"
unlink command
This command must not be enabled if the editing host is in the plaintext-only state.
IE 9 RC unlinks the whole link you're pointing at, while others only unlink the current text. The latter behavior seems less expected, as with createLink, although I can't articulate precisely why. Word 2007 and OpenOffice.org 3.2.1 (Ubuntu) seem to give an option to remove the whole link or none of it, which backs the spec's requirement. See also #whatwg logs starting at 2011-05-13 at 16:53 EDT (UTC-0400).
See comment for the createLink command about indeterm/state/value.
href attribute and is contained in the
active range or is an [=tree/ancestor=]
of one of its [=boundary points=].
An indentation element is either
a [^blockquote^], or a [^div^] that has a
style attribute that sets "margin" or some subproperty of
it.
We need to allow stuff that sets border/padding because WebKit (Chrome 12 dev) sets "border: none; padding: 0px" when indenting. We need to allow stuff that sets classes because WebKit sets class="webkit-indent-blockquote". We need to allow stuff that sets dir because IE9 does. The criteria could probably be tightened up a bit to reduce false positives, but it'll do for now.
A simple indentation element is an indentation element that has no attributes except possibly
style attribute that sets no properties other than
"margin", "border", "padding", or subproperties of those; and/or
dir attribute.
The notions of indentation element and simple indentation element parallel those of modifiable element and simple modifiable element.
listing and xmp are included because otherwise insertParagraph inside them won't work, since paragraphs aren't an allowed child.
A non-list single-line container is an HTML element with [=Element/local name=] "address", "div", "h1", "h2", "h3", "h4", "h5", "h6", "listing", "p", "pre", or "xmp".
A single-line container is either a non-list single-line container, or an HTML element with [=Element/local name=] "li", "dt", or "dd".
The block node of a node node is either a block node or null, as returned by the following algorithm:
Bug 14062. See also Mozilla bug 590640, specifically comments 48 and on.
If a command preserves overrides, then before taking its action, the user agent must record current overrides. After taking the action, if the active range is {{AbstractRange/collapsed}}, it must restore states and values from the recorded list.
All block commands preserve overrides except the insertText
command, which treats overrides specially.
TODO: When breaking a non-inline element out of an inline element, like p in b or whatever, it would make sense to re-wrap the contents in the inline tag.
To fix disallowed ancestors of node:
We often run this algorithm after we move a node someplace, just in case it wound up somewhere it's not supposed to be. This avoids things like unserializable DOMs, blocks nested inside inlines, etc.
This case is really intended to handle stuff like list items or table cells that wander outside their proper place. We generally convert them into [^p^]s.
If node is not an allowed child of any of its [=tree/ancestors=] in the same editing host:
createElement("dl")
on the context object.
Then abort these steps.
There's no reason to change the node to a paragraph if that won't make it an allowed child anyway.
If "p" is not an allowed child of the editing host of node, abort these steps.
Because maybe it somehow wound up as the child of a p, like via insertHTML.
Fix disallowed ancestors of node.
This algorithm implies that we don't support a sublist in the middle of an item, only at the end. For instance,
<li>foo<ol>...</ol>bar</li>
gets transformed to
<li>foo</li><ol>...</ol><li>bar</li>
which in particular creates an extra list marker for "bar". This is okay; we don't need to expose all of HTML's markup abilities through execCommand(). Similarly, the superscript and subscript commands don't allow nesting. I didn't see any way to get a sublist in the middle of an item in Word 2007 or in OpenOffice.org 3.2.1 Ubuntu package, nor in any browser using just execCommand(), so it should be no big problem if we require that such nesting not occur. (Existing browsers behave weirdly and inconsistently when confronted with this kind of nesting.)
The reason we need this is that otherwise it gets very confusing to figure out what happens in cases like trying to outdent
<ol><li>[foo<ol><li>bar]</ol>baz</ol>
If we first normalize, then the natural answer is something like
<p>[foo<ol><li>bar]<li>baz</ol>
but if we don't, we'd have to special-case in the toggle lists and outdent algorithms. This might be worthwhile, but it's not at all clear, and what I have works okay, so I'll stick with it for now.
TODO: Investigate fixing this.
To normalize sublists in a node item:
createElement("li")
on the {{Node/ ownerDocument}} of item,
then insert new item into the
[=tree/parent=] of item immediately
after item.
The selection's list state is returned by the following algorithm:
This is just a helper to tell the state and indeterminacy of
the insertOrderedList command and the insertUnorderedList command:
| ol indeterm | ol state | ul indeterm | ul state | |
|---|---|---|---|---|
| ol | false | true | false | false |
| ul | false | false | false | true |
| mixed | true | false | true | false |
| mixed ol | true | false | false | false |
| mixed ul | false | false | true | false |
| none | false | false | false | false |
The child-of-child case is necessary right now because of the following:
<ol><li>[foo<ol><li>bar]</ol>baz</ol>
With the current (July 2011) block-extend algorithm, this will become:
{<ol><li>foo<ol><li>bar</ol>}baz</ol>
because of the magical li handling in block-extend. We want this to register as ol, because after normalizing sublists it will become
{<ol><li>foo</li><ol><li>bar</ol>}<li>baz</ol>
But the text node "foo" will wind up in node list, and is not the child of an ol. This is all very messy and has to do with questionable decisions about how to handle nested lists.
If every member of node list is either an [^ol^] or the [=tree/child=] of an [^ol^] or the [=tree/child=] of an [^li^] [=tree/child=] of an [^ol^], and none is a [^ul^] or an [=tree/ancestor=] of a [^ul^], return "ol".
This condition and the last are mutually exclusive, so the order is actually irrelevant. Clearly they could only both hold if no member of node list is an ol or ul, so if they both held, every member would have to be either the child of an ol and of a ul, or of an ol and an li, or a ul and an li, or of an li that's the child of both an ol and a ul. This is impossible unless the list is empty, in which case we already aborted.
If every member of node list is either a [^ul^] or the [=tree/child=] of a [^ul^] or the [=tree/child=] of an [^li^] [=tree/child=] of a [^ul^], and none is an [^ol^] or an [=tree/ancestor=] of an [^ol^], return "ul".
When querying the value of justify*, IE9 seems to return boolean false across the board when it doesn't throw exceptions, which it usually does in my tests. Chrome 14 dev returns the string "true" or "false" depending on state, as in other cases, which is useless. Opera 11.11 returns "" across the board. Firefox 6.0a2 behaves like with other command values: it returns "center"/"justify"/"left"/"right" depending on the active range's start node. Since this is the only behavior that's possibly useful, it's what I specced. Firefox ties the value closely to the state, returning true for the state if and only if the value matches the desired value, but this seems less useful than what I've specced for the state.
This API is based on the four-state text-align of CSS 2.1. We do some crude mapping to make it not break too badly with CSS3 values, but it's not going to work well given the design of the API.
The alignment value of a node node is returned by the following algorithm:
This is basically like the resolved value of text-align, but with two key differences. First, it only ever evaluates to center/justify/left/right, since that's the model that the justify commands work with. Second, it ignores inline elements, because text-align has no effect on them and their alignment is actually governed by their nearest block ancestor (if any).
This means there's no applicable style rule, so probably it will wind up left-aligned. Of course this ignores the fact that the alignment will really be "start", so this is wrong for RTL, but it's a pretty marginal corner case anyway. (It will only happen if, e.g., everything up to and including the html and body elements have display: inline or none.)
If node is not an {{Element}}, return "left".
Sometimes one location corresponds to multiple distinct boundary
points. For instance, in the DOM <p>Hello</p>, a boundary point might lie at the
beginning of the text node or the beginning of the element node, but
these don't logically differ much and will appear the same to the
user, so we often want to treat them the same. The algorithms here
allow navigating through such equivalent boundary points, for when we
want to make the selection as inclusive or exclusive as possible. For
deletion, we want to delete as few nodes as possible, so we move the
start node forward and the end node backward. In other cases we might
do the reverse, expanding the selection. In still other cases we
might want to move forward or backward to try getting to a text node.
Given a [=boundary point=] (node, offset), the next equivalent point is either a [=boundary point=] or null, as returned by the following algorithm:
{}<span></span> were
equivalent to <span>{}</span>, it
would also be equivalent to <span></span>{}. This produces very unexpected
results for nodes like <br>.
<span>foo[]</span> is equivalent to
<span>foo{}</span>, which is
equivalent to <span>foo</span>{}.
However, <p>foo{}</p> is
not equivalent to <p>foo</p>{} – the cursor might look like
it's in a visibly different position.
{}<span>foo</span> is equivalent to
<span>{}foo</span>, which is
equivalent to <span>[]foo</span>.
As noted before, though, we don't descend into empty nodes. And
again, {}<p>foo</p> is different
from <p>{}foo</p>.
Given a [=boundary point=] (node, offset), the previous equivalent point is either a [=boundary point=] or null, as returned by the following algorithm:
The first equivalent point of a [=boundary point=] (node, offset) is returned by the following algorithm:
The last equivalent point of a [=boundary point=] (node, offset) is returned by the following algorithm:
A [=boundary point=] (node, offset) is a block start point if either node's [=tree/parent=] is null and offset is zero; or node has a [=tree/child=] with [=tree/index=] offset − 1, and that [=tree/child=] is either a visible block node or a visible [^br^].
A [=boundary point=] (node, offset) is a block end point if either node's [=tree/parent=] is null and offset is node's [=Node/length=]; or node has a [=tree/child=] with [=tree/index=] offset, and that [=tree/child=] is a visible block node.
A [=boundary point=] is a block boundary point if it is either a block start point or a block end point.
When a user agent is to block-extend a [=range=] range, it must run the following steps:
Generally, block commands work on any block that contains part of the selection, even if the selection doesn't include the whole block. This algorithm takes an input range, copies it, stretches out the copy to contain entire blocks, and returns the result. Then the caller will normally use it instead of the range it started with. For instance, if the cursor is collapsed in a text node inside a paragraph, this will generally return a range that includes the whole paragraph.
Two bits of magic worth noting. First, <br> counts as a block delimiter here, since it
looks the same as a block boundary (assuming no margin etc.) and
this is a visual API. We include the <br> as part of the line that precedes it. Second,
if the selection is inside an <li>,
this will extend it to include the whole <li>. This latter point is weird, and I should
re-examine it sometime, but it seems to work.
This just changes something like <div>{<p>foo]</p></div> to
{<div><p>foo]</p></div>.
While start offset is zero and start node's [=tree/parent=] is not null, set start offset to start node's [=tree/index=], then set start node to its [=tree/parent=].
A node node follows a line break if the following algorithm returns true:
A node node precedes a line break if the following algorithm returns true:
To record current overrides:
When restoring, some commands can interfere with others. Specifically, we want to restore createLink before foreColor and underline, and subscript and superscript before fontSize. TODO: This approach only works for default styles (although I'm not sure offhand how we could handle non-default styles in principle).
Firefox 7.0a2 and Opera 11.50 don't honor createLink with collapsed selections. If you insert text, it's not linked. The spec follows Chrome 14 dev. IE9 also ignores createLink with collapsed selections, but its behavior in other cases for collapsed selections is totally different from all other browsers, so it's not a fair comparison.
If there is a value override for "createLink", add ("createLink", value override for "createLink") to overrides.
Firefox 7.0a2 and Opera 11.50 will honor repeated subscript/superscript commands on a collapsed selection, allowing you to nest them. The spec follows the general philosophy that we don't allow users to nest subscript/superscript, so the last one wins. Chrome 14 dev is similar to the spec.
For each command in the list "bold", "italic", "strikethrough", "subscript", "superscript", "underline", in order: if there is a state override for command, add (command, command's state override) to overrides.
To record current states and values:
Thus we will set state overrides based on the first formattable
node, to match values. This means that if you have <p>foo<b>[bar</b>baz]</p> and
hit backspace and hit A, you'll get <p>foo<b>a[]</b></p>, although
bold was previously indeterminate. This is needed to match the
behavior of hitting A straight away, since innerText doesn't
strip wrappers when it invokes "delete the contents".
For each command in the list "bold", "italic", "strikethrough", "subscript", "superscript", "underline", in order: if node's effective command value for command is one of its inline command activated values, add (command, true) to overrides, and otherwise add (command, false) to overrides.
Special case for fontSize, because its values are weird.
Add ("fontSize", node's effective command value for "fontSize") to overrides.
This is wrong: it will convert non-pixel sizes to pixel sizes. But I don't see any way to avoid it. Hopefully it won't come up too often. font-size is a real problem, because the mapping from specified value to computed value is lossy and not fully defined (e.g., how many px is "small"?).
To restore states and values specified by a list overrides returned by the record current overrides or record current states and values algorithm:
queryCommandState(command) returns something different from
override, take the action for command, with
value equal to the empty string.
queryCommandValue(command) returns something not equivalent to
override, take the action for command, with
value equal to override.
This special case is needed because createLink has no value.
Otherwise, if override is a string; and command is "createLink"; and either there is a value override for "createLink" that is not equal to override, or there is no value override for "createLink" and node's effective command value for "createLink" is not equal to override: take the action for "createLink", with value equal to override.
The override will be some CSS value, so we have to convert it to a legacy font size.
Otherwise, if override is a string; and command is "fontSize"; and either there is a value override for "fontSize" that is not equal to override, or there is no value override for "fontSize" and node's effective command value for "fontSize" is not loosely equivalent to override:
If we took the action for a command, we need to reset
node, because it might have changed. For
instance, if the selection was foo[bar]baz, the text node could have been split so
that the first part is now outside the active range.
Set node to the first formattable node effectively contained in the active range, if there is one.
TODO: Consider what should happen for block merging in corner cases like display: inline-table.
To delete the selection, given a block merging flag that defaults to true, a strip wrappers flag that defaults to true, and a string direction that defaults to "forward":
The idea behind this algorithm is self-explanatory, but the details wind up being remarkably complicated.
First, any editable nodes inside the selection will be deleted, and
the selection will be collapsed. By way of contrast, effectively contained tries to expand
the range to include as much as possible, so <p>[foo]</p> contains the <p>. What we do here is contract the range to
include as little as possible, so {<p>foo</p>} contains only foo and doesn't delete the paragraph.
After that, if the selection originally started and ended in
different blocks, and the block merging flag is
true, the end block will get merged into the start block. This is
needed so if the user selects text on several lines and deletes it,
the text immediately that was before the selection winds up on the
same line as the text immediately after it. For example,
<p>fo[o</p><div>b]ar</div>
becomes <p>fo[]ar</p>. This
procedure winds up being tricky, and takes up a large chunk of the
logic.
Tables are a notable special case. If an entire table is contained in the range, it will be deleted. If it's anything less, only the contents of the cells will be deleted and the table structure will be left intact.
The strip wrappers flag controls what happens
if the deletion removes all the contents of an inline element. If
wrappers are being stripped, the empty inline element will be
removed: this is usually what you want, because the user can't
position the selection inside it. But callers like the insertText
command that intend to immediately insert new contents want to
leave the wrappers, so the new contents are wrapped by the same
thing as the old.
Even if strip wrappers is true, the algorithm will set a state override and value override for any styles it winds up removing. This way, if the user deletes a wrapper that adds a style (or link for that matter), then types something, the new text will get the style from the old text.
This is a selection like <span>foo[</span></span>]bar</span>,
where the boundary points are equivalent but not identical. We
just collapse it and abort, since there's nothing to delete.
collapseToStart() on
the context object's
selection.
collapseToEnd() on the
context object's
selection.
The previous two steps are so that we won't leave empty text nodes anywhere.
collapse(start node,
start offset) on the context object's
selection.
extend(end node,
end offset) on the context object's
selection.
When we delete a selection that spans multiple blocks, we merge the end block's contents into the start block, like
<p>fo[o</p><pre>b]ar</pre> -> <p>fo[]ar</p>.
We figure out what the start and end blocks are before we start deleting anything.
We only merge to or from block nodes or editing hosts. (This is
just in case someone makes a span into an editing host and
sticks paragraphs inside it or something . . . we could
probably drop that proviso.) Firefox 7.0a2 ignores the display
property when merging, so it doesn't merge <span style=display:block> but does merge
<p style=display:inline>. This is
undesirable, because it's visually wrong. IE10PP2 and Chrome 14
dev behave more like the spec, and Opera 11.50 seems to be
unable to make up its mind.
If span isn't an allowed child, it's probably something unpleasant like a table row or a list or such. We don't want to merge to or from something like that, because we'd most likely wind up with the wrong type of child somewhere. It should be pretty hard for this to happen given the normalization we do on the selection; I'm not actually sure how it could happen at all, actually, unless you start out with a DOM that has non-allowed children someplace. So it's basically a sanity check.
We don't let either start block or end block be a td or th. This means we'll never merge to or from a td or th. This matches Firefox 5.0a2, and reportedly Word as well. Chrome 13 dev and Opera 11.11 allow merging from a non-table cell end block to a table cell start block, but not vice versa. In IE9 the delete key just does nothing.
If start block is neither a block node nor an [=editing host=], or "span" is not an allowed child of start block, or start block is a [^td^] or [^th^], set start block to null.
Later on we'll restore overrides. This ensures that if we delete inline formatting elements and the user then types something, the typed text will have the same style as before.
As far as I can tell, IE9 and Opera 11.50 don't do this at all. If you delete a selection and then start typing, the new text doesn't take on the styles of the old text.
Firefox 7.0a2 seems to do it for some styles but not others. Strikethrough, superscript, subscript, and links seem to be lost, at a minimum.
The spec goes with something like Chrome 14 dev, which tries to preserve lots of stuff.
Record current states and values, and let overrides be the result.
Now we actually begin deleting things.
This whole piece of the algorithm is based on deleteContents() in DOM Range, copy-pasted and then adjusted to fit.
If start node and end node are the same, and start node is an editable {{Text}} node:
deleteData(start
offset, end offset − start offset) on start
node.
collapseToStart() on
the context object's
selection.
collapseToEnd() on the
context object's
selection.
This is needed to restore any overrides that would otherwise be lost. TODO: In this and similar cases, we could optimize by saving only overrides, not the full state/value.
Restore states and values from overrides.
deleteData() on it, with start
offset as the first argument and ([=Node/length=] of
start node − start offset)
as the second argument.
IE9 doesn't seem to let you do any intercell deletions: the delete key does nothing if you select across multiple cells. Firefox 5.0a2 and Opera 11.11 behave as the spec says, not removing any table things. Chrome 13 dev will remove entire rows if selected. Note that IE, Firefox, Word 2007, and OpenOffice.org 3.2.1 Ubuntu all switch to a magic cell-selection mode when you try to select between cells, at least in some cases, instead of selecting letter-by-letter.
For each node contained in the active range, append node to node list if the last member of node list (if any) is not an [=tree/ancestor=] of node; node is editable; and node is not a [^thead^], [^tbody^], [^tfoot^], [^tr^], [^th^], or [^td^].
Do this before stripping wrappers: see bug 13831.
If the block node of parent has no visible
[=tree/children=], and parent is editable or an [=editing host=], call
createElement("br")
on the context
object and append the result as the last [=tree/child=]
of parent.
Taking insertText to test the case where strip wrappers is
false, with value a: <p>[foo<b>bar</b>]baz becomes
<p>a[]baz per spec, in IE9, and
in Chrome 14 dev. Firefox 7.0a2 and Opera 11.50 make it
<p>a[]<b></b>baz,
with a useless wrapper. <p>foo<b>[bar</b>baz] becomes
<p>foo<b>a[]</b> per
spec and in IE9 and Firefox 7.0a2 and Opera 11.50; in Chrome
14 dev apparently it initially becomes <p>fooa[], but then the style is recreated.
This is detectable if you do something weird like
<span style=color:#aBcDeF>
instead of <b>: it comes
<font class=Apple-style-span
color=#abcdef> or such. I follow IE9 in all cases,
because it makes the most sense.
If strip wrappers is true or parent is not an [=tree/inclusive ancestor=] of start node, while parent is an editable inline node with [=Node/length=] 0, let grandparent be the [=tree/parent=] of parent, then remove parent from grandparent, then set parent to grandparent.
Even if strip wrappers is false, we still want to strip wrappers that aren't [=tree/inclusive ancestors=] of start node. The idea of not stripping wrappers is that we're going to insert new content right afterward, like text or an image, but that new content will be inserted at the start node. Wrappers in other places still need to be removed, because they would otherwise remain empty.
deleteData(0, end offset) on it.
Now we need to merge blocks. The simplest case is something like
<p>fo[o</p><p>bar</p><p>b]az</p>
-> <p>fo</p>{}<p>az</p>
-> <p>fo{}az</p>
where neither block descends from the other. More complicated is something like
foo[<p>]bar</p> -> foo[]bar
or
<p>foo[</p>]bar -> <p>foo[]bar</p>
where one descends from the other.
collapseToStart() on
the context object's
selection.
collapseToEnd() on the
context object's
selection.
We might have added a br to the start/end block in an earlier step. Now we're about to merge the blocks, and we don't want the br's to get in the way. The end block is being destroyed no matter what. If the start block winds up empty after merging, we'll add a new br child at the end so it doesn't collapse.
If start block has one [=tree/child=], which is a collapsed block prop, remove its [=tree/child=] from it.
Just repeatedly blow up the end block in this case.
If start block is an [=tree/ancestor=] of end block:
collapse() on the
context
object's selection, with first argument
start block and second argument the
[=tree/index=] of reference node.
createElement("br")
on the context
object and insert it into end
block's [=tree/parent=] immediately after end block.
In this case, pull in everything that comes after start block, until we hit a br or block node.
Otherwise, if start block is a [=tree/descendant=] of end block:
collapse() on the
context
object's selection, with first argument
start block and second argument start block's [=Node/length=].
In the last case, just move all the children of the end block to the start block, and then get rid of any elements we emptied that way.
Otherwise:
collapse() on the
context
object's selection, with first argument
start block and second argument start block's [=Node/length=].
We might have deleted the contents between two lists, in which case we should merge them. See bug 13976.
createElement("br")
on the context object and
append the result as the last [=tree/child=] of start
block.
To split the parent of a list node list of consecutive [=tree/sibling=] nodes:
This algorithm breaks up the parent of node list. If they're the only children of their parent, the parent is removed entirely. If there are preceding or following siblings, the original parent is left intact as the parent of those siblings. If there are both preceding and following siblings, the original parent is left as the parent of the following siblings and a clone is used for the parent of the preceding siblings.
We make sure not to disrupt the appearance any more than necessary.
Obviously margins or such on the parent will be lost, but the
children will not wind up on the same line as anything they weren't
already on the same line as. E.g., if we split the parent of "bar"
in foo<p>bar</p>, we get
foo<br>bar, not foobar. (This is amazingly complicated and error-prone.)
We don't preserve inline styles: callers that want to do that
should call record the values and
restore the values themselves.
All this is useful in a lot of situations, like for outdenting. For inline formatting commands, we almost always rely on pushing down values instead, since that often leads to tidier markup.
TODO: We insert things after the parent. This is bad, because it will cause them to become part of any ranges that immediately follow. For instance, if we're hitting "bar" in
<div><p>foo<p>bar</div>{<p>baz}
it becomes
<div><p>foo</div>{<p>bar<p>baz}
instead of
<div><p>foo</div><p>bar{<p>baz}
because of how range mutation rules work. This doesn't happen if we insert before. This may or may not be important enough to bother working around.
If the first [=tree/child=] of original parent is not in node list, but its last [=tree/child=] is:
createElement("br")
on the context object
and insert the result immediately after the last member of
node list.
cloneNode(false)
on original parent.
id attribute, unset it.
Notice that a boundary point that was immediately before the element will now be immediately before its children, just because of the regular range mutation rules, without needing to worry about preserving ranges. Likewise for boundary points immediately after the element, if we wind up removing the element in the final step. Preserving ranges is only necessary for the sake of boundary points in the element or its descendants.
For each node in node list, insert node into the [=tree/parent=] of original parent immediately before original parent, preserving ranges.
createElement("br")
on the context object and
insert the result immediately before the first member of
node list.
createElement("br")
on the context object
and insert the result immediately after the last member of
node list.
The parent might be null if it's a br that we removed in the last step, in which case this step isn't necessary.
If node list's last member's {{Node/nextSibling}} is null, but its [=tree/parent=] is not null, remove extraneous line breaks at the end of node list's last member's [=tree/parent=].
To remove a node node while preserving its descendants, split the parent of node's [=tree/children=] if it has any. If it has no [=tree/children=], instead remove it from its [=tree/parent=].
Whitespace in HTML normally collapses. However, if the user hits the space bar twice in an HTML editor, they expect to see two spaces, not one. Even if they hit the space bar once at the beginning or end of a line, it would collapse without special handling. The only good solution here is for the author to set white-space: pre-wrap on the editable area, and on everywhere the content is reproduced. But if they don't, we have to painfully hack around the problem.
This is a basically intractable problem because of the unfortunate
confluence of three factors. One, our characters are Unicode, and
Unicode doesn't know about whitespace collapsing, so it provides no
special characters to control it. Two, HTML itself provides no
features that control whitespace collapsing without undesired side
effects (like inhibiting line breaks or not being allowed inside
<p>). Three, we need to support user
agents that don't reliably support CSS, since that includes many
popular mail clients.
The upshot is we have no good way to control whitespace collapse,
so we rely on the least bad way available: . This doesn't collapse with adjacent
whitespace in browsers, which is good. But it also doesn't allow a
line break opportunity, which is bad. In any run of whitespace that
we don't want to collapse, any two regular spaces must be separated
by an so they don't collapse
together, but we need to carefully limit runs of consecutive
s to minimize the damage to
line-breaking behavior.
The result is an elaborate and meticulously-crafted hodgepodge of bad compromises that frankly isn't worth the effort to explain here. The saving grace is that it all gets disabled if white-space is set to pre-wrap as it should be, so authors can opt out of the insanity. Interested readers will find detailed rationale for the exact sequences required in the comments.
See long comment before insertText.
The canonical space sequence of length n, with boolean flags non-breaking start and non-breaking end, is returned by the following algorithm:
To canonicalize whitespace at (node, offset), given an optional boolean argument fix collapsed space that defaults to true:
First we go to the beginning of the current whitespace run.
Repeat the following steps:
TODO: Following a line break is unlikely to be the right criterion.
Otherwise, if start offset is zero and start node does not follow a line break and start node's [=tree/parent=] is in the same editing host, set start offset to start node's [=tree/index=], then set start node to its [=tree/parent=].
Now we collapse any consecutive spaces, if fix collapsed space is true.
Let end node equal start node and end offset equal start offset.
This tries to delete spaces at the beginning of a line (bug 14119).
Let collapse spaces be true if start offset is zero and start node follows a line break, otherwise false.
TODO: Preceding a line break is unlikely to be the right criterion.
Otherwise, if end offset is end node's [=Node/length=] and end node does not precede a line break and end node's [=tree/parent=] is in the same editing host, set end offset to one plus end node's [=tree/index=], then set end node to its [=tree/parent=].
deleteData(end
offset, 1) on end
node, then continue this loop from the beginning.
We've already stripped leading whitespace, and collapsed consecutive spaces. Now we try to strip any collapsed trailing whitespace (bug 14119 again).
If fix collapsed space is true, then while (start node, start offset) is [=boundary point/before=] (end node, end offset):
deleteData(end
offset, 1) on end
node.
Finally we replace with the canonical sequence.
Let replacement whitespace be the canonical space sequence of length length. non-breaking start is true if start offset is zero and start node follows a line break, and false otherwise. non-breaking end is true if end offset is end node's {{CharacterData/length}} and end node precedes a line break, and false otherwise.
We need to insert then delete, so that we don't change range boundary points. TODO: switch to using "replace data" now that DOM Core has defined that.
Call
insertData(start offset,
element) on
start node.
deleteData(start offset + 1,
1) on start node.
There are two basically different types of indent/outdent: lists,
and everything else. For lists we'll wrap the item in a nested list
to indent, and split its parent to outdent. For everything
else we'll wrap in a <blockquote> to
indent, and try breaking it out of an ancestor indentation element to outdent.
Indenting winds up being pretty simple: just add an appropriate
wrapper. There's not really anything to think about here except
which wrapper we want (<ol> or
<ul> or <blockquote>), and establishing that is not rocket
science.
Outdenting is considerably more complicated. The basic idea we follow is to first find the nearest editable ancestor that's a list or indentation element. If we succeed, and the node we're trying to outdent is the only descendant of the ancestor, of course we can just remove the ancestor and that's that. Otherwise, what we do is remove the ancestor and then indent all its other descendants, much like pushing down values.
But of course, there are complications. We don't always actually
want to remove the closest ancestor that's causing
indentation. For one thing, we prefer ancestors that we can remove
completely, i.e., simple indentation elements. When
outdenting <blockquote><blockquote
id="abc">foo</blockquote></blockquote>,
removing the inner tag would result in <blockquote><div
id="abc">foo</div></blockquote>, since we
don't want to lose the id. Thus we prefer to remove the outer tag
and wind up with <blockquote
id="abc">foo</blockquote>.
Also, if the node we're outdenting is itself a list, we prefer to remove an ancestor indentation element rather than the list. Otherwise, if the user selected some text, indented it, then added a list, there would be no way to remove the indentation without removing the list first. This way, the user could remove the list with the appropriate list-toggling command or remove the indentation with the outdent command.
We have to handle entire lists of siblings at once, or else we'd wind up doing something like
<ol>
{<li>foo</li>
<ol><li>bar</li></ol>}
</ol>
->
<ol><ol>
<li>foo</li>
<li>bar</li>
</ol></ol>
->
<ol><ol><ol>
<li>foo</li>
<li>bar</li>
</ol></ol></ol>
since by the time we got to doing the <ol> that originally contained "bar", we won't remember that we aren't supposed to indent "foo" a second time.
To indent a list node list of consecutive [=tree/sibling=] nodes:
This matches IE9, Firefox 4.0, and Chrome 12 dev. If there's a preceding <li>, Opera 11.10 instead adds the new parent to the end of that <li>, so it's not the child of another list, which is invalid. But the other browsers' way of doing things makes things simpler. E.g., if we want to indent an <li> and it has <ol>/<ul> children, we have to distinguish between the case where we want to indent the whole <li> or only the first part. It also allows things like
<ol><li> foo <ol><li>bar</li></ol> baz </li></ol>
in which case it's unclear what we should do if the user selects "foo" and indents. I've filed a bug on HTML5.
Wrap node list, with
sibling criteria returning true for an
HTML element with [=Element/local
name=] tag and false otherwise, and
new parent instructions returning the
result of calling createElement(tag)
on the {{Node/ ownerDocument}} of first
node.
Firefox 4.0 respects the CSS styling flag for indent, but Chrome 12 dev does not. I always produce blockquotes, even if CSS styling is on, for two reasons. One, IE9 handles inline margin attributes badly: when outdenting, it propagates the margin to the parent, which doesn't actually remove it. Two, in CSS mode I'd want to use <div style="margin: 1em 40px"> to match non-CSS mode, but authors are very likely to want to remove the top/bottom margin, which they can't do if it's not a special tag. Authors who really want divs for indentation could always convert the blockquotes to divs themselves. But if people really want it, I could respect CSS styling mode here too.
The top/bottom margins might be undesirable here, but no more so than for <ol>/<ul>/<p>/etc. Here as there, authors can remove them with CSS if they want.
blockquote indents on both sides, so we don't have to worry about directionality. In theory it would be better if we indented only on the start side, but that requires care to get right in mixed-direction cases. Even once browsers start to support margin-start and so on, we can't use them because a) we have to work okay in legacy browsers and b) it doesn't help if a descendant block has different direction (so should be indented the other way). So let's not worry about it: most browsers don't, and the ones that do get it wrong. Just indent on both sides.
Wrap node list, with
sibling criteria returning true for a
simple indentation
element and false otherwise, and new parent
instructions returning the result of calling createElement("blockquote")
on the {{Node/ownerDocument}} of first node.
Let new parent be the result.
Things that are produced for indentation that we need to consider removing:
For discussion on the list-related stuff, see the comment for insertOrderedList.
Gecko in CSS mode just adds margin properties to random elements that are lying around. We don't attempt to remove those, because 1) the amount and position of the margin can vary (it increases the margin if there's a preexisting one), so it's potentially complicated, and 2) no browser removes such margins on outdent, including Gecko, except for Gecko in CSS mode. TODO: Consider removing it anyway.
To outdent a node node:
The easy case is when the whole element is indented. In this case we remove the whole thing indiscriminately. In the case of blockquotes created by IE, this might change the direction of some children, but then their direction was probably changed incorrectly in the first place, so no harm.
If node is a simple indentation element, remove node, preserving its descendants. Then abort these steps.
This might be a simple indentation element that had style added to it by Firefox in CSS mode, for instance (color, font-family, etc.).
If node is an indentation element:
dir attribute of node, if any.
Approximate algorithms when an ancestor is causing the indentation appear to be:
Overall, all flawed, so I'll make up my own, patterned after pushing down styles. First we search ancestors for a simple indentation element, which we stand a chance of completely removing. Failing that, we look for an indentation element that's not simple, so we can't completely remove it.
Let current ancestor be node's [=tree/parent=].
When asked to outdent a list wrapped in a simple indentation element, Chrome 12 dev removes the list instead of the simple indentation element. Opera 11.10 seems to remove both. IE9 and Firefox 4.0 remove the simple indentation element, as does the spec.
If node is an [^ol^] or [^ul^] and current ancestor is not an editable indentation element:
reversed,
start, and
type attributes of node, if any
are set.
We can't turn it into a div if it's the child of an ol or ul, because that's not allowed: there's no way to group li's (see HTML bug 13128).
If node has attributes, and its [=tree/parent=] is not an [^ol^] or [^ul^], set the tag name of node to "div".
If we get to this point, we have an ancestor to split up.
Append current ancestor to ancestor list.
We can't outdent it yet, because we need its children to remain intact for the loop.
Let original ancestor be current ancestor.
This is the action for the
insertOrderedList command and the insertUnorderedList command, which behave identically
except for which list type they target. It does several things that
vary contextually.
If everything in the selection is contained in the target list type already, this more or less just outdents everything one step. This is relatively simple.
Otherwise, it's slightly more complicated:
First, any lists of the opposite list type (other tag name) get converted to the target list type (tag name). They get merged into a sibling if appropriate, otherwise we set the tag name.
Then we go through all the affected nodes, handling each run of
consecutive siblings separately. Any line that's not already
wrapped in an <li> gets wrapped. If the
parent at this point isn't a list at all, the run gets wrapped in a
list. If it's the wrong type of list, we split the parent and rewrap it in the right
type of list. That's basically it, except that we have to exercise
the usual care to try merging with siblings and so forth.
Research for insertOrderedList/insertUnorderedList: tested the following command sequences in IE9, Firefox 4.0, Chrome 12 dev, Opera 11.10, OpenOffice.org 3.2.1 Ubuntu package, Microsoft Office Word 2007. The commands "ol", "ul", "indent", "outdent" correspond in browsers to "insertOrderedList", "insertUnorderedList", "indent", and "outdent"; in OO.org to "Numbering On/Off", "Bullets On/Off", "Increase Indent", "Decrease Indent"; and in Word to "Numbering", "Bullets", "Increase Indent", "Decrease Indent".
Note: OO has a bunch of extra options, like "Promote One Level", "Demote One Level", "Promote One Level With Subpoints", "Demote One Level With Subpoints", "Insert Unnumbered Entry", "Restart Numbering". The regular "Increase/Decrease Indent" commands work oddly, and I assume they're not really meant to be used inside lists. Thus I also tested with "Promote One Level" and "Demote One Level". These are denoted by OO' instead of OO.
Assume that there are style rules in effect like
ol ol { list-style-type: lower-alpha }
ol ol ol { list-style-type: lower-roman }
This is the default appearance in Word, and I set OO to something similar with Bullets and Numbering → Outline in the list editing toolbox. I'm ignoring bullet style throughout, for no particular reason.
Ignoring the conceptual model of HTML, which users won't understand, here's the conceptual model I've developed for lists: text is divided up into blocks. Each block has an indentation level and a list marker type. The list marker type can be either nothing, ordered, or unordered. A list block cannot have indentation level less than one. Any given piece of text is part of only one block. A block may be visually non-contiguous, such as if a single list block is interrupted by a further-indented block.
To find the right number (or letter) for an ordered-list block, look at the immediately preceding block, but skip over any blocks of higher indentation level. If there is no immediately preceding block, or it's not an ordered-list block, or it has a lower indentation level, the number is 1 (or a, i, etc.). Otherwise, it's the number of the preceding block plus one.
ol/ul commands change the selected block to that list marker type, or remove the list marker type if it's already the chosen type. If the block has indentation level zero, it increases to one.
indent/outdent commands change the selected block's indentation level. If a list block's indentation level is reduced to zero, it's converted to a regular block.
What this means from an HTML perspective, roughly:
Sheesh, lists are complicated.
To toggle lists, given a string tag name (either "ol" or "ul"):
TODO: This overnormalizes, but it seems like the simplest solution for now.
For each item in items, normalize sublists of item.
Convert it to the right name. If possible, we want to merge with a neighboring list of the correct type. Failing that, we set the tag name.
If list's {{Node/ previousSibling}} or {{Node/nextSibling}} is an editable HTML element with [=Element/local name=] tag name:
We exclude indentation elements so that selecting some random text and doing indent followed by insertOrderedList will have the same result as the reverse. Specifically,
<blockquote>[foo]</blockquote> -> <blockquote><ol><li>[foo]</li></ol></blockquote>
per spec and Firefox 4.0 and (more or less) Chrome 12 dev. Opera 11.10 instead does <ol><li>foo</li></ol>, so the indentation vanishes. IE9 does <ol><ol><li>foo</li></ol></ol>, but that doesn't make semantic sense and is different from how it would work if you reversed the commands. OpenOffice.org 3.2.1 (Ubuntu) and Word 2007 both agree with the spec in this case.
For each node node contained in new range, if node is editable; the last member of node list (if any) is not an [=tree/ancestor=] of node; node is not an indentation element; and either node is an [^ol^] or [^ul^], or its [=tree/parent=] is an [^ol^] or [^ul^], or it is an allowed child of "li"; then append node to node list.
We don't want to touch these. E.g., assuming tag name is "ol",
[foo<ol><li>bar</ol>baz] -> <ol><li>[foo<li>bar<li>baz]</ol> not <ol><li>[foo</li><ol><li>bar</ol><li>baz]</ol>.
But
<ul><li>foo<li>[bar</li><ol><li>baz</ol><li>quz]</ul> -> <ul><li>foo</ul><ol><li>[bar</li><ol><li>baz</ol><li>quz]</ol> not <ul><li>foo</ul><ol><li>[bar</ol><ul><ol><li>baz</ol></ul><ol><li>quz]</ol>
If mode is "enable", remove from node list any [^ol^] or [^ul^] whose [=tree/parent=] is not also an [^ol^] or [^ul^].
Accumulate consecutive sibling nodes in sublist, first converting them all to li's (except if they're already lists).
While either sublist is empty, or node list is not empty and its first member is the {{Node/nextSibling}} of sublist's last member:
Thus <p>foo</p> becomes <ol><li>foo</ol> instead of <ol><li><p>foo</ol>, and likewise for div, but other things will be put inside the <li>.
If node list's first member is a [^p^] or [^div^], set the tag name of node list's first member to "li", and append the result to sublist. Remove the first member from node list.
createElement("li") on the context
object. Append the result to sublist.
In this case it's already wrapped properly, nothing more to do.
If sublist's first member's [=tree/parent=] is an HTML element with [=Element/local name=] tag name, or if every member of sublist is an [^ol^] or [^ul^], continue this loop from the beginning.
createElement(tag
name) on the context
object.
Special case: something like
<ol><li>foo</ol><blockquote>[bar]</blockquote>
becomes
<ol><li>foo</li><ol><li>[bar]</ol></ol>
instead of
<ol><li>foo</ol><blockquote><ol><li>[bar]</ol></blockquote>.
We handle the special case in new parent instructions instead of outside because we'd prefer to wind up in a sibling if there is one. We handle only previousSibling, not nextSibling, because we really mean for this to cover something like
[foo<blockquote>bar]</blockquote>
which we'll handle node-by-node. TODO: Maybe we should do this differently, like just special-case simple indentation elements in an earlier part of the algorithm? This way's a bit weird.
If sublist's first member's
[=tree/parent=] is not an editable simple indentation
element, or sublist's first
member's [=tree/parent=]'s {{Node/ previousSibling}} is
not an editable HTML element with [=Element/local
name=] tag name, call createElement(tag
name) on the context
object and return the result.
createElement(tag
name) on the context
object, and append the result as the last
[=tree/child=] of list.
This is the action for the four justify* commands. It's pretty straightforward, with no
notable gotchas or special cases. It works more or less like a
stripped-down version of set the
selection's value, except it gets to be much simpler because it's
much less general. (It's not similar enough to just invoke that
algorithm: too many things differ between block and inline elements.)
There are two basic ways this works in browsers: using the align attribute, and using CSS text-align. IE9 and Opera 11.11 use only the align attribute, Chrome 13 dev uses only text-align, and Firefox 5.0a2 varies based on styleWithCSS. The two ways produce entirely different results, which is a real problem, so I don't think Firefox's approach is tenable. text-align is more valid, and for typical contenteditable cases it works the same. But for cases where you have fixed-width blocks, like tables or just divs with a width set, it behaves differently, and in those cases the align attribute is more useful.
TODO: text-align doesn't behave as expected if there are descendant blocks with non-100% width, like tables. The align attribute behaves a lot more nicely in such cases, but it's not valid. Not clear what to do. For now I've stuck with text-align, just because the cases where it misbehaves can't be created by any sequence of stock execCommand()s that I know of, but this needs more careful consideration. Gecko in CSS mode seems to special-case tables, adding auto margins to the table element to get it to align correctly.
TODO: We could do something along the lines of pushing down values here, although no browser does. In fact, it's very likely this can be rewritten in terms of the inline formatting command primitives, but it's not clear if it would be worth the added complexity.
To justify the selection to a string alignment (either "center", "justify", "left", or "right"):
No browser actually removes center, but it makes sense to do so.
Let element list be a list of all editable {{Element}}s contained in
new range that either has an attribute in the
HTML namespace
whose [=Attr/local name=] is "align", or has a
style attribute that sets "text-align", or is a
center.
style attribute.
center with no attributes, remove it, preserving its descendants.
center with one or more attributes, set the tag name of element to "div".
This could theoretically be necessary, like if it converted "<div align=right>foo</div>bar" to "foo<br>bar". Now we need to select "foo<br>", nor just "foo".
Block-extend the active range, and let new range be the result.
Of tested browsers, only Chrome 13 dev seems to not apply the alignment to nodes that are already aligned. Even then, it does apply it if the alignment is just inherited from the root.
For each node node contained in new range, append node to node list if the last member of node list (if any) is not an [=tree/ancestor=] of node; node is editable; node is an allowed child of "div"; and node's alignment value is not alignment.
Wrap sublist. Sibling criteria returns true for any [^div^] that has one or both of the following two attributes and no other attributes, and false otherwise:
align attribute whose [=Attr/value=] is an
ASCII
case-insensitive match for alignment.
style attribute which sets exactly one CSS
property (including unrecognized or invalid attributes),
which is "text-align", which is set to alignment.
As with inline formatting, I only ever create new elements, and don't ever modify existing ones. This doesn't match how any browser behaves in this case, but for inline formatting it matches everyone but Gecko's CSS mode, so I'm just being consistent.
New parent instructions are to call
createElement("div")
on the context
object, then set its CSS property "text-align" to
alignment and return the result.
When the user inserts whitespace immediately following something that
looks like a URL or e-mail address, we automatically run the createLink
command on it.
An autolinkable URL is a string of the following form:
IE9 and LibreOffice 3.3.4 both have a whitelist of URL schemes. That would be complicated and involve political decisions, so instead, we'll just accept anything that looks like a hierarchical URL scheme. Google Docs is similar (as of November 9, 2011), but it's too lax, and allows characters in the scheme that can't be in a scheme. For non-hierarchical schemes, we just whitelist mailto:, since it's the only common one that makes sense to autolink.
Either a string matching the scheme pattern
from RFC 3986
section 3.1 followed by the literal string ://, or the literal string mailto:; followed by
We don't try to enforce that the URL is anything resembling valid per spec. Too complicated for not enough gain.
Zero or more characters other than space characters; followed by
If the user types a URL followed by some punctuation, we still want to autolink, but we don't want to include the punctuation if it's probably not meant as part of the URL.
IE9 excludes !#&()*+,-.:;<=?@[]^_`{|}~ as trailing
characters from both URLs and e-mails. A trailing " or > will prevent
autolinking, and a trailing $%'/\ is
included in the link.
LibreOffice 3.3.4 excludes trailing !”#'()*+,.:;<=>?[\]^_`{|}~, and prevents
autolinking on $%&-@. It includes a
trailing / in URLs, but it inhibits
linking for e-mails.
Google Docs (as of November 9, 2011) is complicated. Trailing
”’,-. always prevents autolinking of a
URL, and trailing #%/?_ is always
included in a URL. Trailing !&=$()*+:;<>@[\]^`{|}~ prevent autolinking
if there's no ? before them, but are
included in the URL if there is a ?. For
e-mails, _ is included, and everything
else prevents autolinking.
None of these behaviors makes maximal sense. We should exclude
characters if they're more likely as delimiters than actual
trailing characters; include them if they're more likely as
actual trailing characters; and prevent autolinking if their
presence suggests that we're not actually looking at a link or
e-mail address. The lists I made up for URLs are: exclude
trailing !"'(),-.:;<>[]`{}, include
anything else. For e-mail, exclude anything at all.
A character that is not one of the ASCII characters !"'(),-.:;<>[]`{}.
To autolink (node, end offset):
delete command
This is the same as hitting backspace (see Additional requirements). The easy part is if the selection isn't collapsed: just delete the selection. But it turns out rich-text editors have a lot of special behaviors for hitting backspace with a collapsed selection. Most obviously, if there's a text node right before the cursor (maybe wrapped in some inline elements), we delete its last character. But some of the special cases we run into are:
<a> gets removed if you
backspace while the cursor is right after it, so the link
disappears.
<br> or <hr> or <img> gets
deleted.
<li>
or <dt> or <dd> that's at the beginning of a list, outdents
the current block (rather than merging with the previous block).
For all the deletions here, Firefox 7.0a2 will remove wrapper elements like <b> only if they're selected, like {<b>foo</b>}. IE9, Chrome 14 dev, and Opera 11.50 will all remove them even if only their contents are selected, like <b>[foo]</b>. Gecko's behavior in the latter case leaves things like <b>{}</b> in the DOM, which is unhelpful, so I don't.
Needed so that if there are multiple consecutive spaces we backspace over all at once.
Canonicalize whitespace at the active range's [=range/start=].
First go up as high as possible within the current block, then drill down to the lowest possible level, in the hopes that we'll wind up at the end of a text node, or maybe in a br or hr.
Repeat the following steps:
If there's an invisible node somewhere, Firefox 5.0a2 removes that node and then stops, so each backspace removes one invisible node. All others remove the invisible node and then continue on looking for something visible to remove. The spec follows the latter behavior, since it makes more sense to the user. Of course, the definition of "invisible node" is not necessarily anything like the spec's.
If offset is zero and node's {{Node/ previousSibling}} is an editable invisible node, remove node's {{Node/ previousSibling}} from its [=tree/parent=].
When backspacing a link, Firefox 7.0a2, Chrome 14 dev, Opera 11.50, and OpenOffice.org 3.2.1 Ubuntu have no special behavior. IE9 and Word 2007 remove the link instead of deleting its last character. The latter behavior seems more useful and intuitive.
Otherwise, if node has a [=tree/child=] with [=tree/index=] offset − 1 and that [=tree/child=] is an editable [^a^], remove that [=tree/child=] from node, preserving its descendants. Then return true.
At this point, node cannot be an invisible node. There are three cases:
Unlike forwardDelete, there's no special case for diacritics. This means backspacing will just delete the last combining diacritic typed, or the whole character if it's precomposed. This matches everything I tested (IE9, Firefox 7.0a2, Chrome 14 dev, etc.).
If node is a {{Text}} node and offset is not zero, or if node is a block node that has a [=tree/child=] with [=tree/index=] offset − 1 and that [=tree/child=] is a [^br^] or [^hr^] or [^img^]:
collapse(node,
offset) on the context
object's selection.
extend(node,
offset − 1) on the context object's
selection.
At the time of this writing, this should be impossible. Just being safe.
If node is an inline node, return true.
If we're at the beginning of a list, we want to outdent the first list item. This doesn't actually match anyone or anything. Word 2007 and OpenOffice.org 3.2.1 Ubuntu just remove the list marker, which is weird and doesn't map well to HTML. Browsers tend to just merge with the preceding block, which isn't expected.
If node is an [^li^] or [^dt^] or [^dd^] and is the first [=tree/child=] of its [=tree/parent=], and offset is zero:
Annoying hack to prevent the dl from being re-added when fixing disallowed ancestors. In most cases we want a wrapper dl added, but in two cases (delete and insertParagraph) we're actually trying to outdent the list item. TODO: there might be a better way to do this.
If node is a [^dd^] or [^dt^], and it is not an allowed child of any of its [=tree/ancestors=] in the same editing host, set the tag name of node to the default single-line container name and let node be the result.
By this point, we're almost certainly going to merge something, and the only question is what.
Let start node equal node and let start offset equal offset.
At the beginning of an indented block, outdent it, similar to a list item. Browsers don't do this, word processors do. Note: this copy-pastes from the outdent command action.
If offset is zero, and node has an editable [=tree/inclusive ancestor=] in the same editing host that's an indentation element:
This is to avoid stripping a line break from
foo<br><br><table><tr><td>[]bar</table>
and similarly for <hr>. We should just do nothing here.
If the [=tree/child=] of start node with [=tree/index=] start offset is a [^table^], return true.
If you try backspacing into a table, select it. This doesn't match any browser; it matches the recommendation of the "behavior when typing in contentEditable elements" document. The idea is that then you can delete it with a second backspace.
If start node has a [=tree/child=] with [=tree/index=] start offset − 1, and that [=tree/child=] is a [^table^]:
collapse(start
node, start offset − 1) on
the context object's
selection.
extend(start node,
start offset) on the context object's
selection.
Special case:
<p>foo</p><br><p>[]bar</p> -> <p>foo</p><p>[]bar</p>
and likewise for <hr>. But with <img> we merge like in other cases:
<p>foo</p><img><p>[]bar</p> -> <p>foo</p><img>[]bar.
Browsers don't do this consistently. Firefox 5.0a2 doesn't seem to do it at all.
If offset is zero; and either the [=tree/child=] of start node with [=tree/index=] start offset minus one is an [^hr^], or the [=tree/child=] is a [^br^] whose {{Node/previousSibling}} is either a [^br^] or not an inline node:
collapse(start
node, start offset − 1) on
the context object's
selection.
extend(start node,
start offset) on the context object's
selection.
collapse(node,
offset) on the selection.
If you try backspacing out of a list item, merge it with the previous item, but add a line break. Then you have to backspace again if you really want them to be on the same line. This matches Word 2007 and OpenOffice.org 3.2.1 Ubuntu, and also matches "behavior when typing in contentEditable elements", but does not match any browser.
Note that this behavior is quite different from what happens if you actually select the linebreak in between the two lines. In that case, the blocks are merged as normal.
Also note that hitting backspace twice will merge with the previous item. This matches OO.org, but Word will outdent the item on subsequent backspaces. Word's behavior doesn't fit well with the way lists work in HTML, and we probably don't want it.
If the [=tree/child=] of start node with [=tree/index=] start offset is an [^li^] or [^dt^] or [^dd^], and that [=tree/child=]'s {{Node/firstChild}} is an inline node, and start offset is not zero:
If the last child is already a br, we only need to append one extra br. Otherwise we need to append two, since the first will do nothing.
If previous item's {{Node/lastChild}} is
an inline node other than a
[^br^], call createElement("br")
on the context
object and append the result as the last [=tree/child=]
of previous item.
createElement("br")
on the context object
and append the result as the last [=tree/child=] of previous item.
When merging adjacent list items, make sure we only merge the
items themselves, not any block children. We want <li><p>foo<li><p>[]bar to
become <li><p>foo<p>[]bar, not <li><p>foo<br>[]bar or <li><p>foo[]bar. To do the deletion, we
need to wipe out the current selection, so we save it as a range.
Saving it as a node/offset pair isn't enough, because it might be
invalid after we do the deletion. A range will update according
to the range mutation rules.
If start node's [=tree/child=] with [=tree/index=] start offset is an [^li^] or [^dt^] or [^dd^], and that [=tree/child=]'s {{Node/previousSibling}} is also an [^li^] or [^dt^] or [^dd^]:
cloneRange()
on the active range, and let
original range be the result.
collapse(start
node, start offset) on the
context object's
selection.
extend(node,
0) on the context
object's selection.
removeAllRanges() on
the context object's
selection.
addRange(original
range) on the context object's
selection.
General block-merging case.
While start node has a [=tree/child=] with [=tree/index=] start offset minus one:
collapse(start node,
start offset) on the context object's
selection.
extend(node,
offset) on the context object's
selection.
formatBlock command
This command lets you change what block element particular lines are wrapped in. It will convert an existing wrapper if one exists, and otherwise will create a new one.
A formattable block name is "address", "dd", "div", "dt", "h1", "h2", "h3", "h4", "h5", "h6", "p", or "pre".
Tested browser versions: IE9, Firefox 4.0, Chrome 13 dev, Opera 11.10.
Firefox and Chrome will replace a <blockquote> by a <p> or other given tag. IE and Opera will nest the <p> inside instead. The latter makes more sense, given that a) we don't support formatBlock with <blockquote> and b) <blockquote>s are logically different, since they can contain many lines.
Firefox will not convert other tags like <p> to <div>, it will only wrap unwrapped lines in a <div>. Firefox also won't replace <div> by things like <p>, it will nest the <p> inside. The spec follows other browsers.
If you try to convert a <dt> to a <div> or <p> or such, Firefox breaks out of the <dl> entirely, leaving ...<dt><br></dt></dl>. Chrome will convert a <dt> or <dd> to the given element, leaving a <div> or <p> or such as the child of a <dl>. I follow IE/Opera, which only affect the contents of <dt>/<dd> (Firefox behaves this way for <dd> as well, just not <dt>). This means you can get invalid DOMs like <dt><p>foo<p></dt>, but they can be serialized as text/html, so I'm not too fussy.
When it comes to <li>, IE/Opera behave like with <dt>/<dd>, which is how I behave too. Firefox apparently refuses to do anything. Chrome tries to wrap the parent list element, breaking it up if only some of the children are selected; this produces unserializable DOMs if you're wrapping with <p>.
When you're converting multiple blocks at once, Chrome replaces them all by one block with <br> stuck in, like <p>foo</p><p>bar</p> -> <div>foo<br>bar</div>. It wipes out intervening block containers too in some cases. This might make sense for <address>/<h*>/<pre>, but other browsers don't do it.
IE9 requires the brackets. If they're not provided, it does nothing.
If value begins with a "<" character and ends with a ">" character, remove the first and last characters from it.
Opera 11.10 throws NOT_SUPPORTED_ERR for bad elements, all other tested browsers ignore the input. Testing in IE9, Firefox 4.0, Chrome 13 dev, and Opera 11.10, supported elements seem to be:
HTML5 as of May 2011 supports: address, article, aside, blockquote, div, footer, h*, header, hgroup, nav, p, pre, section, which exactly matches Chrome except minus dd/dt/dl.
See mailing list discussion on the subject.
If value is not a formattable block name, return false.
This tries to avoid misnesting if only some lines of an element are selected, so <h1>[foo]<br>bar</h1> becomes <p>[foo]</p><h1>bar</h1> instead of <h1><p>[foo]</p><br>bar</h1> or such. It tries to heuristically distinguish between divs used as line-breakers and divs used as actual wrappers by checking if they have prohibited paragraph children as descendants. It works for address too, in case there are paragraphs nested inside. Thus <address>[foo]<br>bar</address> becomes <p>[foo]</p><address>bar</address>, but <address>[foo]<p>bar</p></address> becomes <address><p>[foo]</p><p>bar</p></address>. Likewise, we don't break things out of lists or tables or such if they happen to be nested in a <div>.
For each node in node list, while node is the [=tree/descendant=] of an editable HTML element in the same editing host, whose [=Element/local name=] is a formattable block name, and which is not the [=tree/ancestor=] of a prohibited paragraph child, split the parent of the one-node list consisting of node.
We have two different behaviors, one for div and p and one for everything else. The basic difference is that for div and p, we assume that it should be one line per element, while for other elements, we put in multiple lines separated by <br>. So if you do formatBlock to p on
<div>foo</div><div>bar</div>
or
foo<br>bar
you get
<p>foo</p><p>bar</p>
but formatBlock to h1 will get you
<h1>foo<br>bar</h1>.
IE9 will just change the elements as they are, so it gives <p>foo</p><p>bar</p> and <h1>foo</h1><h1>bar</h1> for <div>foo</div><div>bar</div>, but <p>foo<br>bar</p> and <h1>foo<br>bar</h1> for foo<br>bar. This is unreasonable, because the two possible inputs here look identical to the user and might have been produced by identical user input.
Firefox 5.0a2 will give results like <p>foo</p><p>bar</p> or <h1>foo</h1><h1>bar</h1> no matter what (modulo oddities in its handling of divs). Opera 11.10 is similar, except it leaves a trailing <br> in the first element.
Chrome 13 dev will give results like <p>foo<br>bar</p> or <h1>foo<br>bar</h1> no matter what.
The specced behavior is a compromise between the existing behaviors, predicated on the fact that <h1>foo</h1><h1>bar</h1> almost never makes sense, and <p>foo<br>bar</p> isn't usually what's wanted either.
While node list is not empty:
If you try to format a single-line container with no children, IE10PP2 inserts an nbsp before formatting. (It uses nbsp instead of <br> to make blocks not collapse, so the equivalent for us would be to insert a <br>.) Firefox 7.0a2 and Opera 11.50 make the element disappear. Chrome 14 dev leaves it alone and doesn't format it. I follow Firefox/Opera just because it's the simplest given how I happen to have written the spec, and it's a corner case, so exact behavior isn't important.
For blocks that contain only a collapsed whitespace node, IE10PP2 and Firefox 7.0a2 convert them like normal. Chrome 14 dev and Opera 11.50 leave it alone and don't format it. I go with the majority, which is again simpler to spec.
Let sublist be the [=tree/children=] of the first member of node list.
createElement(value)
on the context
object. Then fix
disallowed ancestors of the result.
Firefox 6.0a2 throws, Chrome 14 dev always returns false, Opera 11.11 doesn't support indeterm to start with, IE9 was uncooperative in testing so I'm not sure what it does. I'm speccing it just because it makes sense.
IE9 returns human-readable strings like "Normal" (p/div/etc.), "Formatted" (pre), "Heading 1" (h1), etc. Firefox 6.0a2 and Chrome 14 dev both return the appropriate tag name in lowercase, or the empty string if there is no appropriate tag. Opera 11.11 behaves the same, but with uppercase.
IE9 looks like it recognizes address, h*, pre, dd, dt, ol, ul, and dir, with everything else registering as "Normal". Firefox 6.0a2 recognizes only the arguments it accepts for formatBlock, namely address, h*, p, and pre. Chrome 14 dev recognizes address, div, h*, dd, dl, dt, p, pre plus lots of random other stuff like blockquote and section. I'll go with everything that execCommand("formatblock") accepts as an argument, which at the time of this writing means what Firefox supports plus div.
Opera 11.11 doesn't require it be editable, so it will return "DIV" instead of "" for <div contenteditable>foo</div>.
While node's [=tree/parent=] is editable and in the same editing host as node, and node is not an HTML element whose [=Element/local name=] is a formattable block name, set node to its [=tree/parent=].
Chrome 14 dev will report "div" for <div><ol><li>foo</ol></div> or such. Opera 11.11 reports "". IE and Firefox didn't cooperate with testing. Opera makes more sense, and matches the fact that formatBlock now doesn't recognize such a div as a formatBlock candidate, so Opera it is.
We don't really need to specify "editable" here, since it has to be editable if we got to this point.
If node is an editable HTML element whose [=Element/local name=] is a formattable block name, and node is not the [=tree/ancestor=] of a prohibited paragraph child, return node's [=Element/local name=], converted to ASCII lowercase.
forwardDelete command
This is the same as hitting the delete key (see Additional requirements). It behaves
much the same as the delete command, except of course backwards. Also, some
of the special cases for backspacing don't apply, as noted in the
comments. The one special case you get when deleting forward but not
backward is that if the cursor is before a grapheme cluster that
consists of multiple characters, like a base character with combining
diacritics, we delete the diacritics too. (Backspacing just deletes
the last diacritic, so you have to backspace several times to remove
the whole cluster.)
Copy-pasted from delete, see there for comments.
No special link behavior for forwardDelete here, unlike delete.
Otherwise, if node has a [=tree/child=] with [=tree/index=] offset and that [=tree/child=] is neither a block node nor a [^br^] nor an [^img^] nor a collapsed block prop, set node to that [=tree/child=], then set offset to zero.
Firefox 7.0a2, Chrome 14 dev, Word 2007, and OpenOffice.org 3.2.1 Ubuntu act as the spec says, getting rid of all diacritics on forward delete. IE9 and Opera 11.50 have no special case and just delete the next character. I go with Firefox/Chrome/Word/OO.
However, when I actually type in the text box as opposed to running semi-automated tests, IE9 has magical behavior: it replaces the base character with something that looks like ◌ U+25CC DOTTED CIRCLE. Further strikes of the delete key remove the diacritics, and the circle vanishes along with the last of them. I wasn't able to get it to actually replace the base character, so I'm not sure what the point is. The circle doesn't seem to appear in the DOM, and apparently it disappears in some circumstances. This might be worth standardizing somehow, I don't know.
TODO: The way we remove diacritics is probably not right. We probably want to normalize to grapheme cluster boundaries, using UAX#29 or something. We also need to handle non-BMP stuff. The idea is that if the cursor is before a character that precedes a combining mark, you need to delete the combining mark too.
While end offset is not node's [=Node/length=] and the end offsetth code unit of node's {{CharacterData/ data}} has general category M when interpreted as a Unicode code point, add one to end offset.
collapse(node,
offset) on the context
object's selection.
extend(node,
end offset) on the context object's
selection.
collapse(node,
offset) on the context
object's selection.
extend(node,
offset + 1) on the context object's
selection.
No special list-item behavior for forwardDelete here, unlike delete.
Let end node equal node and let end offset equal offset.
No special indentation element behavior for forwardDelete here, unlike delete.
If the [=tree/child=] of end node with [=tree/index=] end offset minus one is a [^table^], return true.
collapse(end node,
end offset) on the context object's
selection.
extend(end node,
end offset + 1) on the context object's
selection.
Note, any br will do here: a br immediately after a block is always significant.
If offset is the [=Node/length=] of node, and the [=tree/child=] of end node with [=tree/index=] end offset is an [^hr^] or [^br^]:
collapse(end node,
end offset) on the context object's
selection.
extend(end node,
end offset + 1) on the context object's
selection.
collapse(node,
offset) on the selection.
No special list-item behavior for forwardDelete here, unlike delete.
While end node has a [=tree/child=] with [=tree/index=] end offset:
collapse(node,
offset) on the context object's
selection.
extend(end node,
end offset) on the context object's
selection.
indent command
This command must not be enabled if the editing host is in the plaintext-only state.
For repeated indentation, everyone except Opera that outputs <blockquote>s just puts them at the outermost possible location, which works well. Opera puts them in the innermost position, which is broken, because it will even put them inside <p> (which will not round-trip through text/html serialization).
Gecko in CSS mode messes up by adding margins even to things like <blockquote> that already have margins from CSS rules, instead of nesting a div, so it doesn't actually increase the indentation. However, if an element has an explicit left margin (assuming LTR), it will increase the margin to 80px, so it works with WebKit's blockquotes.
We have two strategies for handling directionality: always indent on both sides (Firefox non-CSS, Opera) or try to figure out heuristically which side we want (IE, Firefox CSS). The latter approach is only possible by adding extra markup and complexity, so for now we'll take the easy way out and go with just indenting on both sides.
This reasoning doesn't discuss lists. For research on lists, see the comment for insertOrderedList. List handling is more complicated and I wound up differing from all browsers in lots of ways.
TODO: This overnormalizes, but it seems like the simplest solution for now.
For each item in items, normalize sublists of item.
Without this step, the last child of the previous sibling might be a list, which the li wouldn't get appended to.
If the first visible member of node list is an [^li^] whose [=tree/parent=] is an [^ol^] or [^ul^]:
insertHorizontalRule command
This command must not be enabled if the editing host is in the plaintext-only state.
You'd think interop here would be simple, right? Nope: we have three different behaviors across four browsers. Opera 11.00 is the only one that acts more or less like the spec. IE9 and Chrome 12 dev treat the value as an id, which is weird and probably useless, so I don't do it. Firefox 4.0 produces <hr size=2 width=100%> instead of <hr>, which is also weird and almost definitely useless, so I don't do it. Then you have the varying behavior in splitting up parents to ensure validity . . .
collapse(start node,
start offset) on the context object's
selection.
extend(end node,
end offset) on the context object's
selection.
We don't want to call insertNode at the start or end of a text node, because that will leave an empty text node.
If the active range's [=range/start
node=] is a {{Text}} node and its [=range/start offset=] is zero,
call collapse() on the context object's
selection, with first argument the
active range's [=range/start node=]'s
[=tree/parent=] and second argument the active range's [=range/start node=]'s
[=tree/index=].
collapse() on the context object's
selection,
with first argument the active range's
[=range/start node=]'s [=tree/parent=], and the second argument one
plus the active range's [=range/start
node=]'s [=tree/index=].
createElement("hr")
on the context object.
insertNode(hr)
on the active range.
IE9 and Chrome 13 dev seem to never break up any ancestors, which can lead to unserializable DOMs like <hr> inside <p>. Opera 11.11 seems to always break up parents going all the way up to the contenteditable root, even ones like <div> that can contain <hr>. Firefox 5.0a2 acts the most sensibly: it only breaks up things like <p> or <b> that shouldn't contain <hr>. The spec goes with Firefox here (although the list of what to break up isn't precisely identical).
Fix disallowed ancestors of hr.
collapse() on the context object's
selection,
with first argument hr's [=tree/parent=] and the
second argument equal to one plus hr's
[=tree/index=].
insertHTML command
Not supported by IE9. Handling of disallowed children is interesting:
Chrome 14 dev and Opera 11.11 do this even if the value is empty. Firefox 5.0a2 throws an exception.
Firefox 7.0a2 and Chrome 14 dev do strip wrappers here, so inserting HTML in the place of <b>[foo]</b> will remove the <b>. Opera 11.50 keeps the wrappers. I follow the majority and leave the "strip wrappers" flag true.
TODO: This has some interesting consequences. For instance, table cells and similar will just vanish if they're not in an appropriate place; and inside a script or style or xmp or such, the argument will effectively be HTML-escaped before use. Some of these consequences might be undesirable.
Let frag be the result of calling
createContextualFragment(value) on
the active range.
Firefox 5.0a2 also seems to not add empty elements like <b></b>, but Chrome 13 dev and Opera 11.11 do.
If last child is null, return true.
This is so we don't get something like
<div>[foo]</div>
-> <div>{}<br></div>
-> <div><p>Some HTML{}</p><br></div>
with an extra bogus line break at the end.
If the active range's [=range/start node=] is a block node:
We could canonicalize whitespace after inserting the fragment, but let's not. If the author wants HTML, give them HTML behavior. When asked to replace a paragraph's contents with a single space, Firefox 7.0a2 does so but inserts a <br> before it (not after); Chrome 14 dev does so and doesn't insert a <br>, so the paragraph collapses; Opera 11.50 doesn't insert the space at all, and just inserts a <br>. Correct behavior is to insert a space, then insert a <br> after it in the next step because it's an invisible node.
Call insertNode(frag)
on the active range.
In case we remove all the contents, then remove the extra <br>, then only add a comment or something. In that case we want to re-add the extra <br>. We don't try fixing the actual inserted content: that's the author's lookout.
If the active range's [=range/start
node=] is a block node with no visible [=tree/children=], call createElement("br")
on the context object
and append the result as the last child of the active range's [=range/start node=].
Need to do this before fixing disallowed ancestors, since otherwise the last child might have been removed (e.g., it's an li).
Call collapse() on the context object's
selection, with last
child's [=tree/parent=] as the first argument and one plus
its [=tree/index=] as the second.
We want to fix all descendants, not just children. Consider <div><li>foo</li></div>, for example.
Fix disallowed ancestors of each member of descendants.
insertImage command
This command must not be enabled if the editing host is in the plaintext-only state.
Similar logic to createLink, except even more compelling, since an HTML document linking to itself as an image is just silly. In fact, the current HTML spec instructs UAs to not even try displaying the image, and just fail immediately if the URL is empty. Firefox 4b11 silently does nothing on an empty string, but the other three browsers I tested stick in the <img> anyway.
If value is the empty string, return false.
Firefox 7.0a2 seems to strip the wrapper or not depending on the exact positioning of the selection: <b>{foo}</b> yes, <b>[foo]</b> no. Chrome 14 dev seems to strip the wrapper regardless. Opera 11.50 seems to keep the wrapper, but place the image outside it. I didn't get IE to cooperate with my tests. I chose to leave wrappers across the board because they might be meaningful: e.g., a background-color when the image is small or not fully opaque.
Delete the selection, with strip wrappers false.
Same logic as with insertHTML.
If range's [=range/start node=] is a block node whose sole [=tree/child=] is a [^br^], and its [=range/start offset=] is 0, remove its [=range/start node=]'s [=tree/child=] from it.
createElement("img")
on the context object.
No alt text, so it's probably invalid. This matches all browsers.
Run setAttribute("src",
value) on img.
This winds up putting it at the original start point of the active range, as currently specced. This matches IE9 and Firefox 5.0a2. Chrome 13 dev puts it at the end point, and Opera 11.11 puts it in between (where the range would collapse if you called deleteContents()).
Run insertNode(img)
on range.
An image could be inserted inside a link, with either this command or insertHTML. On Chrome 51 dev, inserting an image (with insertImage or insertHTML) inside a link will remove the parent link. Firefox 48 allows this nesting.
getSelection() on the
context object.
collapse() on selection, with first argument equal to the [=tree/parent=]
of img and the second argument equal to one plus
the [=tree/index=] of img.
insertLineBreak command
This is the same as hitting Shift-Enter or such (see Additional requirements). It deletes
the selection, and replaces it with a <br>. No real complications.
Only implemented in WebKit (Chrome 14 dev). Other tests are entirely manual (i.e., actually hitting Shift-Enter instead of running a command). There's a surprisingly large amount of interop.
IE9 is tripped up by <xmp>, and also often doesn't add an extra <br> when the one it just inserted is extraneous.
Firefox 6.0a2 doesn't notice if you're trying to put the <br> in a bad place, which can result in unserializable DOMs.
Chrome 14 dev inserts a literal linebreak for pre and xmp and maybe other similar elements. This doesn't seem very useful, so I don't bother.
Opera 11.11 isn't heedful of <xmp>, and treats <pre> somewhat oddly.
IE9 doesn't strip wrappers (IE10PP2 didn't work in tests). Firefox 7.0a2 strips wrappers inconsistently depending on the exact selection endpoints. Chrome 14 dev strips wrappers but recreates any styles using new wrappers. Opera 11.50 strips all wrappers.
Delete the selection, with strip wrappers false.
script, xmp, table, . . .
If the active range's [=range/start node=] is an {{Element}}, and "br" is not an allowed child of it, return true.
We don't want to call insertNode at the start or end of a text node, because that will leave an empty text node.
If the active range's [=range/start
node=] is a {{Text}} node and its [=range/start offset=] is zero,
call collapse() on the context object's
selection, with first argument equal to
the active range's [=range/start
node=]'s [=tree/parent=] and second argument equal to the
active range's [=range/start node=]'s
[=tree/index=].
collapse() on the context object's
selection,
with first argument equal to the active
range's [=range/start node=]'s [=tree/parent=] and second
argument equal to one plus the active
range's [=range/start node=]'s [=tree/index=].
createElement("br")
on the context object.
insertNode(br)
on the active range.
collapse() on the context object's
selection,
with br's [=tree/parent=] as the first argument
and one plus br's [=tree/index=] as the second
argument.
createElement("br")
on the context object and
let extra br be the result, then call
insertNode(extra
br) on the active
range.
insertOrderedList command
This command must not be enabled if the editing host is in the plaintext-only state.
Action: Toggle lists with tag name "ol", then return true.
Firefox 6.0a2 sort of supports this, but it throws exceptions most of the time. It has the quirk that even if there are no ol's around, it will say it's indeterminate if there are some things that are ul's and some that are not lists at all, but this doesn't make sense and I don't duplicate it. No one else supports indeterminate for insert*List, but it makes sense if you support state.
Indeterminate: True if the selection's list state is "mixed" or "mixed ol", false otherwise.
IE9 throws exceptions in most cases, Firefox 6.0a2 in some cases as well, for no apparent reason. Ignoring those, the spec basically matches all browsers, except with a few weird random mismatches that looked like browser bugs to me.
State: True if the selection's list state is "ol", false otherwise.
insertParagraph command
This is the same as hitting enter (see Additional requirements). The general rule is that we find the nearest single-line container ancestor, clone it and insert the clone after it, and then move all the contents after the cursor (along with the cursor itself) to the clone. But there are a few special cases:
<address>, <listing>, and <pre>,
we add a <br> instead of cloning it.
These are all elements that are meant to contain multiple lines,
not have one line per element.
<dt> or <dd>, the new
element is the opposite type, so you naturally switch between
entering terms and definitions.
There are three major behaviors here. Firefox 5.0a2 behaves identically to execCommand("formatBlock", false, "p"), which is not really useful. IE9 actually just overwrites the selection with an empty paragraph element, which seems not very useful either. Chrome 13 dev and Opera 11.10 behave basically the same as if the user hit the Return key. This latter behavior seems much more useful, even though it's horribly misnamed, so it's what I'll spec. Comments about IE/Firefox are based on manual tests, where I hit Enter instead of running commands.
(Actually, Opera doesn't behave quite the same for insertParagraph and line breaks. But it's pretty close, and I expect the differences are bugs.)
Then, of course, we have several flavors of line-breaking behavior to choose from. Firefox prefers <br>s, unless it's in the middle of a <p> or something. Opera and IE like <p>. Chrome prefers <div>. And there are lots of subtleties besides. I go with IE/Opera-style behavior, as discussed in a whatwg thread.
Update August 2016: The consensus of current browsers is now to use div as the separator, not p, so the spec is updated accordingly.
splitText(offset)
on node.
collapse(node,
offset) on the context object's
selection.
If container is an editable single-line container in the same editing host as node, and its [=Element/local name=] is "p" or "div":
We add the default wrapper in this case.
If container is not editable or not in the same editing host as node or is not a single-line container:
Ideally, we should normalize things so that the cursor is never in a weird place after deletion, but let's be safe and bail out if we do hit this scenario. It's not clear if we need this line in the long term, but at the time of this writing there's at least one corner case where deleting can leave the cursor inside a <tr>.
If tag is not an allowed child of the active range's [=range/start node=], return true.
createElement(tag)
on the context
object.
insertNode(container)
on the active range.
createElement("br")
on the context
object, and append the result as the last
[=tree/child=] of container.
collapse(container, 0) on the context
object's selection.
TODO: It is not at all obvious that this is the correct list of nodes in all cases. It should probably work because of how the block-extend algorithm works, but further thought would be good.
While the {{Node/nextSibling}} of the last member of node list is not null and is an allowed child of "p", append it to node list.
createElement(tag)
on the context
object. Set container to the result.
IE9 and Chrome 13 dev just break <pre> up into multiple <pre>s. Firefox 5.0a2 and Opera 11.10 insert a <br> instead, treating it differently from <p>. The latter makes more sense. What might make the most sense is to just insert an actual newline character, though, since this is a pre after all . . .
IE9 and Chrome 13 dev also break <address> up into multiple <address>es. Firefox 5.0a2 inserts <br> instead. Opera 11.10 nests <p>s inside. I don't like Opera's behavior, because it means we nest formatBlock candidates inside one another, so I'll go with Firefox.
listing and xmp work the same as pre in all browsers. For Firefox and Opera, this results in trying to put a br inside an xmp, so I go with IE/Chrome for xmp.
TODO: In cases where hitting enter in a header doesn't break out of the header, we should probably follow this code path too, instead of creating an adjoining header. No browser does this, though, so we don't.
If container's [=Element/local name=] is "address", "listing", or "pre":
createElement("br")
on the context object.
insertNode(br)
on the active range.
collapse(node,
offset + 1) on the context object's
selection.
Necessary because adding a br to the end of a block element does nothing if there wasn't one there already. A single newline immediately preceding a block boundary does nothing.
If br is the last [=tree/descendant=] of
container, let br be
the result of calling createElement("br")
on the context
object, then call insertNode(br)
on the active range.
Including dt/dd here follows Firefox 5.0a2, as with the special dt/dd handling below.
If container's [=Element/local name=] is "li", "dt", or "dd"; and either it has no [=tree/children=] or it has a single [=tree/child=] and that [=tree/child=] is a [^br^]:
createElement("br")
on the context object
and append the result as the last [=tree/child=] of container.
Annoying hack to prevent the dl from being re-added when fixing disallowed ancestors. In most cases we want a wrapper dl added, but in two cases (delete and insertParagraph) we're actually trying to outdent the list item. TODO: there might be a better way to do this.
If container is a [^dd^] or [^dt^], and it is not an allowed child of any of its [=tree/ancestors=] in the same editing host, set the tag name of container to the default single-line container name and let container be the result.
We don't want the start to be just inside a node, because if it is, we'll leave behind an empty element either in the new or old container. Empty block nodes are fine, and we'll add a [^br^] later, but empty inline nodes are bad, since the user can't interact with them.
While new line range's [=range/start offset=] is zero and its [=range/start node=] is not a prohibited paragraph child, set its [=range/start=] to ([=tree/parent=] of [=range/start node=], [=tree/index=] of [=range/start node=]).
IE9 makes a new header if there's a trailing <br>. Firefox 5.0a2, Chrome 13 dev, and Opera 11.10 do not, and I follow them, since it makes more sense (such a <br> is invisible).
If the [=Element/local name=] of container is "h1", "h2", "h3", "h4", "h5", or "h6", and end of line is true, let new container name be the default single-line container name.
This step and the next follow Firefox 5.0a2. IE9 and Chrome 13 dev act as though these two lines were not present (they clone the existing element). Opera 11.10 nests a <p> inside. Firefox is the most useful, assuming a definition list somehow winds up inside the content (like via formatBlock).
Otherwise, if the [=Element/local name=] of container is "dt" and end of line is true, let new container name be "dd".
createElement(new
container name) on the context object.
id attribute, unset it.
TODO: This blows up any ranges (other than the selection, which we reset), and can alter non-editable nodes, and maybe other bad stuff. May or may not be the best solution. The intermediate fragment is also possibly black-box detectable by DOM mutation events, but I like to pretend those don't exist.
Let frag be the result of calling
extractContents()
on new line range.
id attribute (if any) of each {{Element}}
[=tree/descendant=] of frag that is not in
contained nodes.
appendChild(frag)
on new container.
Needed in case we have something like <ol><li><p>[]foo</ol>, which
becomes <ol><li><p><li><p>foo</ol>.
In this case we want to add the [^br^] to the [^p^], not the
[^li^]. Likewise for <ol><li><p>foo[]</ol>.
While container's {{Node/lastChild}} is a prohibited paragraph child, set container to its {{Node/lastChild}}.
lastChild
is a prohibited paragraph
child, set new container to its
{{Node/lastChild}}.
createElement("br")
on the context object,
and append the result as the last [=tree/child=] of container.
These two steps follow Firefox 5.0a2, Chrome 13 dev, and Opera 11.10. IE9 instead inserts an which magically does not appear in innerHTML. In all cases, the reason is that an empty block box in CSS will have zero height, so the user won't be able to put the selection cursor inside it.
If new container has no visible [=tree/children=], call createElement("br")
on the context object,
and append the result as the last [=tree/child=] of new container.
collapse(new container,
0) on the context
object's selection.
insertText command
This is the same as typing text (see Additional requirements). If the input string is more than one character, first we split it up into one execution per character, for simplicity. The general rule is then that we record each command's state override or value override, insert the new character and select it, restore any overrides that we saved, and collapse the selection to its end.
The idea of the override business is that the user might run a command like bold when the selection is collapsed. There's nothing to bold in that case, but if the user runs bold and then types a character, they expect it to be bold. Thus we save the requested state in an override and restore it when the user types. Deleting things can also set overrides, if the deleted text was styled.
Whitespace is a special case. The note for canonical space sequences gives some of the background. If the user tries typing a space, we make it non-breaking so it doesn't collapse with anything, then canonicalize whitespace around the insertion point so line breaking isn't adversely affected.
One last special case is a newline. For that we just pass off to
the insertParagraph command.
Supported only by WebKit. Tests in other browsers were manual.
TODO: This doesn't work well if the input contains things that aren't supposed to appear in HTML, like carriage returns or nulls. Nor is it going to work well if the current cursor position is in between two halves of a non-BMP character. This will result in unserializability. The current spec disregards this, as Chrome 14 dev does. (It's not relevant to other browsers, since they don't support this as a command.)
Important issue: non-breaking space fun! The issue: if the user hits space twice, they expect it to create two spaces, not collapse. Also, if they're at the beginning or end of a line and hit space, again, they expect it not to collapse. Since we don't want to require that all contenteditable element contents always be used only with white-space: pre-wrap, we need to convert to and from non-breaking spaces.
But there's a catch: you can't just make spaces non-breaking willy-nilly, because that doesn't just stop the space from collapsing, it also prevents breaking. (Chrome 14 dev actually cheats here: in contenteditable, it doesn't collapse nbsp, but breaks after it like a regular space.) The upshot of this is that any nbsp needs to be followed by a space, or else it might end up at the beginning of a line and be visible there; and it needs to be preceded by a space, or else it might break a line prematurely. How to achieve both of these goals when there are an even number of spaces to display is left as an exercise for the reader.
Browsers vary greatly in how they handle all this, of course!
The basic philosophy of IE9 is that if you're inserting a space, and one or both of the neighboring characters is a space, change the neighboring characters to non-breaking spaces. This breaks if one of the neighboring characters is part of a run of collapsed whitespace: "foo []bar" becomes "foo []bar", which converts one visible space to three.
Firefox 6.0a2 will sometimes convert the space you're inserting to an nbsp, sometimes convert neighboring spaces to nbsps, and sometimes convert neighboring nbsps to spaces. I cannot discern any clear reason to when it chooses what, except that it seems to prefer runs of nbsp's followed by a single space (although not always). I didn't find any outright bugs, except the inevitable ones like nbsp's sometimes being right after letters.
Chrome 14 dev tries to normalize everything to look like " ...", alternating with space then nbsp. Unfortunately, it does so buggily, because it converts collapsed spaces to nbsp's, so inserting a space before " " makes it into " ", which changes one visible space to four (or arbitrarily many).
Opera 11.11 has varying behavior, like Firefox and Chrome. Like Firefox, I didn't discern an obvious pattern.
This was all discussed.
Unfortunately, we're stuck with this nbsp stuff, because of 1) legacy reasons, 2) mail clients might not support CSS equivalents, 3) authors might not know to apply any CSS to wherever the content is eventually used. The behavior I decided on to minimize the evil is as follows:
This avoids nbsp at the end of a run except where it's needed, so words won't appear indented if they wrap to the next line. It avoids more than two nbsp's in a row, so there won't be huge chunks of space that get wrapped all at once. And it avoids nbsp at the beginning of a run except where it's needed or if there are only two spaces in the run, so words won't have to wrap unnecessarily.
This is still a huge headache, though.
Chrome 14 dev does the deletion even if the value is empty. Of course, other browsers don't expose this as an execCommand(), so no one else has any defined behavior in this case at all, so I follow Chrome.
IE9, Firefox 7.0a2, Chrome 14 dev, and Opera 11.50 all don't strip wrappers, except that as usual, Gecko does if you select the whole wrapper, like {<b>foo</b>}. Also, Chrome 14 dev seems to strip the wrapper and try recreating the style in cases like <b>[foo</b>bar], where it starts in a wrapper but ends after it; this doesn't always work so well, so I don't do it. Firefox 7.0a2 also has the deletion set overrides for indeterminate state commands, so if you run insertText on [foo<b>bar</b>baz] it will make the result bold.
These things don't make any sense to me, so I don't do them. I set overrides based on the first editable text node in the range when deleting; preserve any wrappers at the start of the range; and restore the overrides in case preserving the wrappers isn't enough (like if they weren't set by deletion at all). This behavior seems to closely match IE9.
Delete the selection, with strip wrappers false.
insertText
command, with value equal to
el.
TODO: WebKit also does magic for tabs, wrapping them in a whitespace-preserving span. Should we?
If value is a newline (U+00A0), take the
action for the insertParagraph command and return true.
Just to be tidy, add to an existing text node if there is one. Firefox 5.0a2 only adds to an existing one if the range is in a text node. IE9, Chrome 14 dev, and Opera 11.11 also add to an existing text node if the range is in an element adjacent to a text node. If there are two text nodes and it's in between, like foo{}bar, IE and Opera add to the first, Chrome adds to the second, although it probably doesn't matter in practice exactly which we choose.
If node has a [=tree/child=] whose [=tree/index=] is offset − 1, and that [=tree/child=] is a {{Text}} node, set node to that [=tree/child=], then set offset to node's [=Node/length=].
collapse(node,
offset) on the context object's
selection.
insertData(offset,
value) on node.
collapse(node,
offset) on the context
object's selection.
extend(node,
offset + 1) on the context object's
selection.
If some text is inserted into <p><br></p> or similar, we no longer need the <br>.
If node has only one [=tree/child=], which is a collapsed line break, remove its [=tree/child=] from it.
createTextNode(value)
on the context
object.
insertNode(text)
on the active range.
collapse(text,
0) on the context
object's selection.
extend(text,
1) on the context
object's selection.
collapseToEnd() on the
context object's
selection.
insertUnorderedList command
This command must not be enabled if the editing host is in the plaintext-only state.
See comments for insertOrderedList.
Action: Toggle lists with tag name "ul", then return true.
Indeterminate: True if the selection's list state is "mixed" or "mixed ul", false otherwise.
State: True if the selection's list state is "ul", false otherwise.
justifyCenter command
This command must not be enabled if the editing host is in the plaintext-only state.
Action: Justify the selection with alignment "center", then return true.
This roughly matches Chrome 14 dev, although not exactly. Firefox 6.0a2 always returns false.
As a general rule, ignoring nodes with children saves us from treating <div align=left><div align=center>foo</div></div> as though it's indeterminate. Chrome 14 dev seems to only pay attention to text nodes, instead, or something like that. At any rate, it fails on images. Firefox 6.0a2 (for state and value) gets tripped up by examples like the one given.
If we ever support centering of tables and similar, we'd want to pay attention even to some nodes that do have children.
Indeterminate: Return false if the active range is null. Otherwise, block-extend the active range. Return true if among visible editable nodes that are contained in the result and have no [=tree/children=], at least one has alignment value "center" and at least one does not. Otherwise return false.
IE9 throws exceptions in almost every case when querying the state of justify*, and Opera 11.11 returns false in every case except some seemingly random crazy ones.
Firefox 6.0a2 returns true for the state of justify* if anything in the range has the right alignment, not if everything does. This isn't consistent with how state works for the inline commands, nor with WebKit.
Chrome 14 dev counts text-align on inline elements, which is wrong, because the property has no effect. It also counts it on non-editable elements, which is wrong, because then the state for justify* wouldn't necessarily be true after executing it. (Chrome actually does align the non-editable elements, but that's just a bug.) Chrome further returns false for justify* if the justification is just the default inherited justification, e.g., left for LTR. This doesn't seem to make sense either.
State is kind of redundant here, because it's true if and only if indeterminate is false and the value is equal to the desired value. However, I'll support it anyway, since Gecko/WebKit do.
State: Return false if the active range is null. Otherwise, block-extend the active range. Return true if there is at least one visible editable node that is contained in the result and has no [=tree/children=], and all such nodes have alignment value "center". Otherwise return false.
Not bidi-safe, but it's a pretty marginal corner case where it fails. Firefox 6.0a2 behaves weirdly here: it keys off the start node of the active range, even if that's not contained. Thus {<div align=center>foo</div>} has value "left" and indeterminate false, which would suggest that the whole selection is aligned left, but that's not the case. Chrome 14 dev returns the state cast to a string, as usual. Opera 11.11 always returns the empty string.
Value: Return the empty string if the active range is null. Otherwise, block-extend the active range, and return the alignment value of the first visible editable node that is contained in the result and has no [=tree/children=]. If there is no such node, return "left".
justifyFull command
This command must not be enabled if the editing host is in the plaintext-only state.
Action: Justify the selection with alignment "justify", then return true.
Indeterminate: Return false if the active range is null. Otherwise, block-extend the active range. Return true if among visible editable nodes that are contained in the result and have no [=tree/children=], at least one has alignment value "justify" and at least one does not. Otherwise return false.
State: Return false if the active range is null. Otherwise, block-extend the active range. Return true if there is at least one visible editable node that is contained in the result and has no [=tree/children=], and all such nodes have alignment value "justify". Otherwise return false.
Value: Return the empty string if the active range is null. Otherwise, block-extend the active range, and return the alignment value of the first visible editable node that is contained in the result and has no [=tree/children=]. If there is no such node, return "left".
justifyLeft command
This command must not be enabled if the editing host is in the plaintext-only state.
Action: Justify the selection with alignment "left", then return true.
Indeterminate: Return false if the active range is null. Otherwise, block-extend the active range. Return true if among visible editable nodes that are contained in the result and have no [=tree/children=], at least one has alignment value "left" and at least one does not. Otherwise return false.
State: Return false if the active range is null. Otherwise, block-extend the active range. Return true if there is at least one visible editable node that is contained in the result and has no [=tree/children=], and all such nodes have alignment value "left". Otherwise return false.
Value: Return the empty string if the active range is null. Otherwise, block-extend the active range, and return the alignment value of the first visible editable node that is contained in the result and has no [=tree/children=]. If there is no such node, return "left".
justifyRight command
This command must not be enabled if the editing host is in the plaintext-only state.
Action: Justify the selection with alignment "right", then return true.
Indeterminate: Return false if the active range is null. Otherwise, block-extend the active range. Return true if among visible editable nodes that are contained in the result and have no [=tree/children=], at least one has alignment value "right" and at least one does not. Otherwise return false.
State: Return false if the active range is null. Otherwise, block-extend the active range. Return true if there is at least one visible editable node that is contained in the result and has no [=tree/children=], and all such nodes have alignment value "right". Otherwise return false.
Value: Return the empty string if the active range is null. Otherwise, block-extend the active range, and return the alignment value of the first visible editable node that is contained in the result and has no [=tree/children=]. If there is no such node, return "left".
outdent command
This command must not be enabled if the editing host is in the plaintext-only state.
TODO: This overnormalizes, but it seems like the simplest solution for now.
For each item in items, normalize sublists of item.
This step is kind of weird. For regular outdenting, we start at the inside and outdent going out, so that we remove the innermost indentation, on the theory that that will produce the cleanest markup (remove the most nodes). For lists, we remove the outermost indentation, because it makes a difference whether we remove inner or outer indentation, and logically we want to remove outer. E.g.,
<ol><li>foo</li><ul><li>bar</li></ul></ol>
should become
foo<ul><li>bar</li></ul>
not
foo<ol><li>bar</li></ol>.
But this is a bit weird and I'm wondering if it's really correct. TODO: Reexamine this.
For each node node contained in new range, append node to node list if the last member of node list (if any) is not an [=tree/ancestor=] of node; node is editable; and either node has no editable [=tree/descendants=], or is an [^ol^] or [^ul^], or is an [^li^] whose [=tree/parent=] is an [^ol^] or [^ul^].
copy command
Action: The user agent must either copy the current selection to the clipboard as though the user had requested it, or [=exception/throw=] a {{"SecurityError"}} exception.
If an implementation supports the document.execCommand method and allows calling it with the commands "copy", the implementation must trigger the copy action, which again will dispatch the "copy" clipboard event, if the "copy" action did not throw a SecurityError exception.
These are the steps to follow when triggering copy actions through the document.execCommand() API:
Copy commands triggered from document.execCommand() will only affect the contents of the real clipboard if the event is dispatched from an event that is trusted and triggered by the user, or if the implementation is configured to allow this. How implementations can be configured to allow write access to the clipboard is outside the scope of this specification.
IE9 supports copy with a security warning.
cut command
Action: The user agent must either copy the current selection to the clipboard and then delete it, as though the user had requested it, or [=exception/throw=] a {{"SecurityError"}} exception.
If an implementation supports the document.execCommand method and allows calling it with the commands "cut", the implementation must trigger the cut action, which again will dispatch the "cut" clipboard event.
These are the steps to follow when triggering cut actions through the document.execCommand() API:
Cut commands triggered from document.execCommand() will only affect the contents of the real clipboard if the event is dispatched from an event that is trusted and triggered by the user, or if the implementation is configured to allow this. How implementations can be configured to allow write access to the clipboard is outside the scope of this specification.
IE9 supports cut with a security warning.
paste command
Action: The user agent must either delete the selection and then paste the clipboard's contents to the current cursor position, as though the user had requested it, or [=exception/throw=] a {{"SecurityError"}} exception.
If an implementation supports the document.execCommand method and allows calling it with the commands "paste", the implementation must trigger the paste action, which again will dispatch the "paste" clipboard event.
These are the steps to follow when triggering paste actions through the document.execCommand() API:
Paste commands triggered from document.execCommand() will only give access to the contents of the real clipboard if the event is dispatched from an event that is trusted and triggered by the user, or if the implementation is configured to allow this. How implementations can be configured to allow read access to the clipboard is outside the scope of this specification.
IE9 supports paste with a security warning. Firefox reportedly only supports it if you set a pref.
defaultParagraphSeparator
command
This is a new feature, added by request in bug 15527. (Opera already had an o-defaultblock command that worked similarly.) If you are implementing this, please make sure to file any feedback as bugs. The spec is not finalized yet and can still be easily changed.
Action: Let value be converted to ASCII lowercase. If value is then equal to "p" or "div", set the context object's default single-line container name to value, then return true. Otherwise, return false.
Value: Return the context object's default single-line container name.
redo command
Action: As defined by the UndoManager specification.
selectAll command
This is totally broken: if executed inside an editing host, it has to select the editing host contents, not the whole document. See bug.
Tested using roughly this.
The behavior here is relatively simple and largely matches implementations.
TODO: Is this right even for framesets?
Let target be the body element of the context object.
TODO: Is this right even for documents whose root element is not an HTML element?
If target is null, let target be the context object's {{Document/documentElement}}.
getSelection() on the
context object, and
call removeAllRanges() on the
result.
getSelection()
on the context object,
and call selectAllChildren(target) on the result.
styleWithCSS command
IE9 and Opera 11.00 don't support this command. By and large, they act the way Gecko and WebKit do when styleWithCSS is off. Gecko invented it, and WebKit also supports it. The default in Firefox 4.0 is off, while all other browsers behave like the default is on (and IE/Opera give no way to turn it off), so I default it to on.
Handling of value matches Firefox 5.0a2. Chrome 13 dev treats the case-sensitive string "true" as true, the case-sensitive string "false" as false, and does nothing for any other string. I went with Gecko because this way there are only two possible effects, not three, which makes it easier to reason about and debug. Also, Gecko made up the command, so this is probably more web-compatible. Cursory searches of Google Code and GitHub suggest that authors almost always pass a boolean as the third argument when using styleWithCSS, in which case the two behaviors work the same.
Action: If value is an ASCII case-insensitive match for the string "false", set the CSS styling flag to false. Otherwise, set the CSS styling flag to true. Either way, return true.
This follows Chrome 13 dev. Firefox 5.0a2 doesn't support queryCommandState() for styleWithCSS.
State: True if the CSS styling flag is true, otherwise false.
undo command
Action: As defined by the UndoManager specification.
useCSS command
[=Action=]: If value is an [=ASCII case-insensitive=] match for the string "false", set the [=CSS styling flag=] to true. Otherwise, set the [=CSS styling flag=] to false. Either way, return true.
This command works the same as [=the styleWithCSS command|styleWithCSS=] but with the opposite values and with no queryCommandState() support. Authors are encouraged to use [=the styleWithCSS command=] instead.
It has been suggested that some things here need to be platform-dependent, not fully standardized. For now I'm standardizing them anyway, because the large majority of behavior should be platform-agnostic. If anyone has suggestions as to particular things that should be left up to platform behavior, please say so.
When the user instructs the user agent to insert a line break inside an
[=editing host=], such as by pressing the Enter key while the cursor is
in an editable node, the user agent must call execCommand("insertparagraph") on the
relevant [=document=].
When the user instructs the user agent to insert a line break inside an
[=editing host=] without breaking out of the current block, such as by
pressing Shift-Enter or Option-Enter while the cursor is in an editable node, the user agent must call execCommand("insertlinebreak") on the
relevant [=document=].
When the user instructs the user agent to delete the previous character
inside an [=editing host=], such as by pressing the Backspace key while
the cursor is in an editable node, the user agent must call execCommand("delete") on the relevant
[=document=].
When the user instructs the user agent to delete the next character
inside an [=editing host=], such as by pressing the Delete key while
the cursor is in an editable node, the user agent must call execCommand("forwarddelete") on the
relevant [=document=].
When the user instructs the user agent to insert text inside an
[=editing host=], such as by typing on the keyboard while the cursor is
in an editable node, the user agent must call execCommand("inserttext",
false, value) on the relevant
[=document=], with value equal to the text the user
provided. If the user inserts multiple characters at once or in quick
succession, this specification does not define whether it is treated as
one insertion or several consecutive insertions.
The user agent may allow the user to make other changes to editable
content, such as causing Ctrl-B to call execCommand("bold"),
when the editing host is in the
true state. Any such change must
be accomplished by calling execCommand(), so that in particular,
"beforeinput" and "input" events fire as appropriate. The command invoked should be one of the standard commands defined in this specification
if possible, and otherwise must be a vendor-specific command.
Thanks to: