This specification defines additions to events for text and related input to allow for the monitoring and manipulation of default browser behavior in the context of text editor applications and other applications that deal with text input and text formatting. This specification builds on the UI events spec [[!UI-EVENTS]].

Input Events Level 2 replaces the first version of Input Events [[INPUT-EVENTS]] and includes:

The test suite and implementation reports for the Input Events specification are still work in progress.

Introduction

This document describes editing related additions to 2 events - Input and beforeinput which are described in the UI events spec [[!UI-EVENTS]]. The goal of these events is to allow authors to understand and/or override default edit behavior both before and after editing occurs.

Definitions

DataTransfer
A DataTransfer object contains richtext and plaintext data for some inputtypes. [[!DATA-TRANSFER]]
express intention
A user can express an intention to execute a specific editing operation by means of keyboard, IME, speech, or similar method. Specific input actions are mapped to intentions following platform-specific conventions.
kill buffer

This definition is not normative.

A kill buffer is a in-memory store of richtext content that is separate from the clipboard which allows for the temporal storage of content that was deleted using specific deletion commands. The user can replace the current selection with the content held in the kill buffer by indicating an intention to yank the kill buffer.

Problems solved

This section is not normative.

Creating a webbased texteditor requires a considerable amount of JavaScript on top of the browser code, among other things because:

  1. Browsers do not handle all editing operations the same way.
  2. Browsers are often buggy in the way they handle certain editing operations.
  3. Individual sites may have custom preferences for how they want to handle certain editing operations.
  4. The development of high-level text editing features in browsers has not followed the principles laid out in the Extensible Web Manifesto in that development of these features has not always been in coordination with the needs of the web developer community.

This spec seeks to alleviate the problem by providing a simple way for web developers to both override browser handling of all user input related to text editing through the beforeinput event, and to monitor what browsers have changed in the DOM due to user input trough the input event.

Use cases

This section is not normative.

  1. Creating a JavaScript text editor in which the <strong>-tag is used instead of the <b>-tag to mark text that the user marks as bold, using any browser-builtin way to mark a text as bold, without having access to all existing browsers.
  2. Creating a JavaScript text editor which works with a data model in the background where JavaScript takes care of rendering changes to the edited text to the DOM.
  3. Creating a JavaScript editor which only allows a subset of richtext editing (for example: bold is allowed, but italic not).
  4. Creating a collaborative editor in which JavaScript is used to render changes to the DOM, based on user intentions with users using different browsers with different ways of expressing specific intentions.
  5. Creating a JavaScript editor with different user access options, where some users only can add or delete text and other users only can add or remove certain types of formatting.

Input Event Types

Input events are sent before (beforeinput event) and after (input event) a user attempts to edit the markup. This includes insertion and deletion of content, and formatting changes.

Input events are dispatched [[!UI-EVENTS]] on elements that act as editing hosts, including elements with the contenteditable attribute set, textarea elements, and input elements that permit text input.

Interface InputEvent

                partial interface InputEvent {
                    readonly attribute DOMString     inputType;
                    readonly attribute DataTransfer? dataTransfer;
                    sequence<StaticRange> getTargetRanges();
                };

                partial dictionary InputEventInit {
                    DOMString inputType = "";
                    DataTransfer? dataTransfer = null;
                    sequence<StaticRange> targetRanges = [];
                };
            

The InputEvent and InputEventInit objects are defined in [[!UI-EVENTS]].

The attributes inputType, dataTransfer and targetRanges of InputEventInit initialize the corresponding attributes of the InputEvent object.

Overview

This section is not normative.

The following table provides a summary of when the data and dataTransfer attributes contain contents and when they are null as well as when the getTargetRanges() method returns an empty or non-empty Array, based on the inputType.

Editing host inputType data dataTransfer getTargetRanges()
Contenteditable "insertText", "insertCompositionText", "insertFromComposition", "formatSetBlockTextDirection", "formatSetInlineTextDirection", "formatBackColor", "formatFontColor", "formatFontName", "insertLink" Yes null Non-empty Array
Contenteditable "insertFromPaste", "insertFromDrop", "insertReplacementText", "insertFromYank" null Yes Non-empty Array
<textarea>, <input type="text"> "insertText", "insertCompositionText", "insertFromComposition", "insertFromPaste", "insertFromDrop", "insertReplacementText", "insertFromYank", "formatSetBlockTextDirection", "formatSetInlineTextDirection", "formatBackColor", "formatFontColor", "formatFontName", "insertLink" Yes null Empty Array
All "historyUndo", "historyRedo" null null Empty Array
Contenteditable All Remaining null null Non-empty Array
<textarea>, <input type="text"> All Remaining null null Empty Array
Attributes

inputType holds the type of input. During initialization, the user agent [[!UI-EVENTS]] is responsible for populating this field as follows:

The cancelability if the beforeinput event depends on the inputType. The inputType MUST be one of the inputType values.

The inputType to be picked depends on the user's expression of intention, whether or not the editing takes place during an IME composition and the state of the selection.

This specification defines the inputType values as the values in the inputType column of the following table.

inputType User's expression of intention Part of IME composition beforeinput cancelable State of selection
"insertText" insert typed plain text No Yes Any
"insertReplacementText" replace existing text by means of a spell checker, auto-correct or similar No Yes Any
"insertLineBreak" insert a line break No Yes Any
"insertParagraph" insert a paragraph break No Yes Any
"insertOrderedList" insert a numbered list No Yes Any
"insertUnorderedList" insert a bulleted list No Yes Any
"insertHorizontalRule" insert a horizontal rule No Yes Any
"insertFromYank" replace the current selection with content stored in a kill buffer No Yes Any
"insertFromDrop" insert content into the DOM by means of drop No Yes Any
"insertFromPaste" paste No Yes Any
"insertTranspose" transpose the last two characters that were entered No Yes Any
"insertCompositionText" replace the current composition string Yes No Any
"insertFromComposition" insert into the DOM a finalized composed string that will not form part of the next composition string Yes Yes Any
"insertLink" insert a link No Yes Any
"deleteByComposition" remove a part of the DOM in order to recompose this part using IME Yes Yes Any
"deleteCompositionText" delete the current composition string before commiting a finalized string to the DOM Yes No Any
"deleteWordBackward" delete a word directly before the caret position No Yes Collapsed
"deleteWordForward" delete a word directly after the caret position No Yes Collapsed
"deleteSoftLineBackward" delete from the caret to the nearest visual line break before the caret position No Yes Collapsed
"deleteSoftLineForward" delete from the caret to the nearest visual line break after the caret position No Yes Collapsed
"deleteEntireSoftLine" delete from to the nearest visual line break before the caret position to the nearest visual line break after the caret position No Yes Collapsed
"deleteHardLineBackward" delete from the caret to the nearest beginning of a block element or br element before the caret position No Yes Collapsed
"deleteHardLineForward" delete from the caret to the nearest end of a block element or br element after the caret position No Yes Collapsed
"deleteByDrag" remove content from the DOM by means of drag No Yes Any
"deleteByCut" remove the current selection as part of a cut No Yes Any
"deleteContent" delete the selection without specifying the direction of the deletion and this intention is not covered by another inputType No Yes Non-collapsed
"deleteContentBackward" delete the content directly before the caret position and this intention is not covered by another inputType or delete the selection with the selection collapsing to its start after the deletion No Yes Non-collapsed
"deleteContentForward" delete the content directly after the caret position and this intention is not covered by another inputType or delete the selection with the selection collapsing to its end after the deletion No Yes Non-collapsed
"historyUndo" undo the last editing action No Yes Any
"historyRedo" to redo the last undone editing action No Yes Any
"formatBold" initiate bold text No Yes Any
"formatItalic" initiate italic text No Yes Any
"formatUnderline" initiate underline text No Yes Any
"formatStrikeThrough" initiate stricken through text No Yes Any
"formatSuperscript" initiate superscript text No Yes Any
"formatSubscript" initiate subscript text No Yes Any
"formatJustifyFull" make the current selection fully justified No Yes Any
"formatJustifyCenter" center align the current selection No Yes Any
"formatJustifyRight" right align the current selection No Yes Any
"formatJustifyLeft" left align the current selection No Yes Any
"formatIndent" indent the current selection No Yes Any
"formatOutdent" outdent the current selection No Yes Any
"formatRemove" remove all formatting from the current selection No Yes Any
"formatSetBlockTextDirection" set the text block direction No Yes Any
"formatSetInlineTextDirection" set the text inline direction No Yes Any
"formatBackColor" change the background color No Yes Any
"formatFontColor" change the font color No Yes Any
"formatFontName" change the font-family No Yes Any
Other specifications may expand on this definition.
The existence of the above mentioned inputTypes does not mean that any given implementation will support all of these. But if a given browser supports an editing operation which potentially leads to a change of the DOM, it MUST dispatch [[!UI-EVENTS]] the corresponding beforeinput and input events.
If the selection is collapsed, "deleteContentBackward" will be used both when the user asks for text deletion within a text node, and when the user shows the intention to deletion of more complex elements or merge paragraphs if the caret is at the start of a text node. In some scripts, backward deletion within a text node with a collapsed selection will delete a code point rather than a grapheme. A grapheme can consist of several characters, where each character corresponds to a code point. The getTargetRanges() method can be used to find out how many characters the browser will remove by default if deleting within a text node.
If the selection is collapsed, "deleteContentForward" will be used both when the user asks for text deletion within a text node, and when the user shows the intention to deletion of more complex elements or merge paragraphs if the caret is at the end of a text node. In some scripts, forward deletion within a text node with a collapsed selection will delete a grapheme rather than a code point. A grapheme can consist of several characters, where each character corresponds to a code point. The getTargetRanges() method can be used to find out how many characters the browser will remove by default if deleting within a text node.

data holds information plaintext data related to what is to be added to the document.

inputType Editing host data
"insertText", "insertCompositionText" or "insertFromComposition" Any the plain text string to be inserted
"insertFromPaste", "insertFromDrop", "insertTranspose", "insertReplacementText" or "insertFromYank" input or textarea the plain text string to be inserted
"formatSetInlineTextDirection" or "formatSetBlockTextDirection" Any "ltr", "rtl", "auto" or "null"
"formatBackColor" or "formatFontColor" Any a string containing an RGB function call [[!CSS-COLOR-4]] corresponding to the proposed color
"formatFontName" Any the proposed value of the font-family CSS property
"insertLink" Any the url of the proposed link
All remaining Any null

dataTransfer holds information about richtext and plaintext data that is to be taken from or added to the document in a DataTransfer object if there is relevant data.

inputType Editing host dataTransfer
"insertFromPaste", "insertFromDrop", "insertTranspose", "insertReplacementText" or "insertFromYank" contenteditable A prepopulated DataTransfer object so that:
  1. The DataTransfer object's drag data store item list contains one entry with the drag data item type string "text/html", whose kind is Plain Unicode string, and whose data is a HTML representation of the content that is in the clipboard, or in the kill buffer, to be dropped or otherwise the content that is to be added. [[!HTML]]
  2. The DataTransfer object's drag data store item list contains one entry with the drag data item type string "text/plain", whose kind is Plain Unicode string, and whose data is a plain text representation of the content that is to be pasted, dropped or otherwise added. [[!HTML]]
All remaining Any null
Methods
inputType Editing host Response of getTargetRanges()
"historyUndo" or "historyRedo" Any empty Array
All remaining contenteditable an Array of StaticRanges [[!STATIC-RANGE]] associated with event
All remaining input or textarea an empty Array

returns , unless the inputType is "historyUndo" or "historyRedo" or the editing host is not a contenteditable element, in which case it returns an empty Array.

Event definitions

beforeinput
Type beforeinput
Interface InputEvent
Sync / Async Sync
Bubbles Yes
Trusted Targets Any Element with contenteditable attribute enabled.
Default action [[!UI-EVENTS]] Varies: 'Update the DOM' for contentEditable=typing editing hosts for inputTypes "insertCompositionText" and "deleteCompositionText". 'Update the DOM element' for contentEditable="true" editing hosts for all inputTypes. None otherwise.
Context
(trusted events)
  • InputEvent.data: the string containing the data that was added to the element, which MAY be null if it doesn't apply.
  • InputEvent.dataTransfer: richtext data added or removed from element, which MAY be null if it doesn't apply.
  • InputEvent.getTargetRanges(): returns an arrays of Static Cranges which will be affected by the change to the DOM if it is not canceled.

A user agent MUST dispatch [[!UI-EVENTS]] this event when the user has attempted to input in a contenteditable element. It does not necessarily mean the user agent [[!UI-EVENTS]] will then update the DOM.

A user agent MUST NOT dispatch [[!UI-EVENTS]] this event due to events that are not caused by attempted user input, such as system events.

input
Type input
Interface InputEvent
Sync / Async Sync
Bubbles Yes
Trusted Targets Any Element with contenteditable attribute enabled.
Default action [[!UI-EVENTS]] None
Context
(trusted events)
  • InputEvent.data: the string containing the data that was added to the element, which MAY be null if it doesn't apply.
  • InputEvent.dataTransfer: richtext data added or removed from element, which MAY be null if it doesn't apply.

A user agent [[!UI-EVENTS]] MUST dispatch [[!UI-EVENTS]] this event immediately after the DOM has been updated due to a user expressed intention to change the document contents which the browser has handled.

Event order during IME composition

An IME composition causes several beforeinput events, not all of which can be canceled.

  1. If the composition is starting with an empty initial composition string (i.e. the composition is not recomposing an existing range of the DOM), this step is skipped.

    1. The UA extracts the initial composition string from the DOM.
    2. A beforeinput event with the inputType "deleteByComposition" is dispatched [[!UI-EVENTS]].
    3. Unless the beforeinput event has been canceled, the initial composition string is removed from the DOM.
    4. Unless the beforeinput event has been canceled, an input event with the inputType "deleteByComposition" is dispatched [[!UI-EVENTS]].

    This note is not normative.

    The default action for this beforeinput event is the removal of the targetRanges from the DOM (i.e. the initial composition string will be removed from the DOM).

    The beforeinput event can be canceled. Canceling the event will prevent the browser from removing the initial composition string from the DOM. Canceling or handling the event will not prevent the composition from taking place or influence the contents of the initial composition string.

  2. A compositionstart event is dispatched. [[!UI-EVENTS]].

  3. If the composition has an empty initial composition string, this step is skipped.

    1. A beforeinput event with the inputType "insertCompositionText" is dispatched [[!UI-EVENTS]] with the data attribute set to the initial composition string.
    2. The DOM is updated with the insertion of the initial composition string at the start of the selection.
    3. An input event with the inputType "insertCompositionText" is dispatched [[!UI-EVENTS]]

    This note is not normative.

    Notice that the beforeinput event cannot be canceled.

  4. With each DOM update of the composition string:

    1. A beforeinput event with the inputType "insertCompositionText" is dispatched [[!UI-EVENTS]] with the data attribute set to the updated contents of the composition text.
    2. A compositionupdate event is dispatched. [[!UI-EVENTS]].
    3. The DOM is updated.
    4. An input event with the inputType "insertCompositionText" is dispatched [[!UI-EVENTS]].

    This step is repeated as long as no text is to be committed to the DOM (i.e. is made to be part of the DOM outside the range controlled by the composition).

  5. When a part or the entire composition string is to be committed to the DOM:

    1. A beforeinput event with the inputType "deleteCompositionText" is dispatched [[!UI-EVENTS]].
    2. The contents of the range controlled by the composition process is removed from the DOM.
    3. A beforeinput event with the inputType "insertFromComposition" is dispatched [[!UI-EVENTS]] with the data attribute set to the part of the final composition string that is to be committed to the DOM.
    4. Unless the beforeinput event with the inputType "insertFromComposition" has been canceled, the DOM is updated with the part of the composition string that is to be committed to the DOM inserted at the start of the selection.
    5. A compositionend event is dispatched. [[!UI-EVENTS]].
    6. Unless the beforeinput event with the inputType "insertFromComposition" has been canceled, a input event with the inputType "insertFromComposition" is dispatched
  6. If only a part of the composition string was committed to the DOM, while another part is not yet to be committed, the process starts over from step 3 with the non-committed part of the final composition string as the new initial composition string.

This note is not normative.

Note that while every composition only has one compositionstart event, it may have several compositionend events.

Privacy and security considerations

This section is not normative.

There are no known security or privacy impacts of this feature beyond fingerprinting [[fingerprinting-guidance]] techniques that already are available through existing events, such as the keydown and keypress [[UI-EVENTS]] events.

If this feature replaces existing events, it MAY lead to a decline in available fingerprinting [[fingerprinting-guidance]] techniques, as users' intentions are recorded, and not the particular type of hardware they used to express this intention.

Acknowledgements

Thanks to: Michael Aufreiter, Adrian Bateman, Oliver Buchtala, Robin Berjon, Enrica Casucci, Bo Cupp, Domenic Denicola, Emil Eklund, Olivier Forget, Aryeh Gregor, Marijn Haverbeke, Yoshifumi Inoue, Koji Ishii, Gary Kacmarcik, Ian Kilpatrick, Frederico Caldeira Knabben, Takayoshi Kochi, Piotrek Koszuliński, Travis Leithead, Grisha Lyukshin, Miles Maxfield, Chaals McCathie Nevile, Masayuki Nakano, Ryosuke Niwa, Julie Parent, Ben Peters, Florian Rivoal, Morgan Smith, Hallvord R. M. Steen, Johan Sörlin, Cristian Talau, Dave Tapuska, Ojan Vafai, Léonie Watson, Xiaoqian Wu, Chong Zhang, Joanmarie, and everyone in the Editing Taskforce for their input and feedback.