Provide page list navigation

Important Information about Techniques

See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.2 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.2.

Applicability

Content structured in HyperText Markup Language (HTML).

This technique relates to Success Criterion 2.4.13: Page Break Navigation (Sufficient).

Description

The objective of this technique is to ensure that a page list navigation aid is provided and that it includes a list of all the available locations in the digital publication.

The page list provides a way to locate static page break locations (i.e., where each new page begins) within a digital publication. These locations typically come from a print equivalent of the edition and allow synchronization in, for example, mixed print-digital environments such as schools and universities.

The source of pagination is not limited to print but could match up to any statically paginated alternative, such as a PDF or even a fixed-layout EPUB (i.e., where the content does not reflow to fit the available screen size).

The order of the page break locations in a digital publication is not sequential in all cases, and not all page breaks may be represented. Publishers often rearrange and remove content from the paginated source content when creating a digital version.

Page lists are a central feature of many digital publishing formats. EPUB 3 defines the page list in its navigation document,[1] while EPUB 2 and DAISY 3 use the pageList element in the NCX.[2]

The DPUB-ARIA module also includes a doc-pagelist role for identifying the navigation element containing the page list.[3]

Examples

Example 1: Example 1 – Page list in HTML publications

To add a page list to a web-based document, the role "doc-pagelist" is added to the element (typically a nav element) that encloses the list and its title.

<nav role="doc-pagelist" aria-labelledby="pglist">
 <h2 id="pglist">Page List</h2>
 <ol>
   <li><a href="intro.xhtml#pg1">1</a></li>
   <li><a href="intro.xhtml#pg2">2</a></li>
   …
 </ol>
</nav>

The destinations of the page list links are usually explicit page break markers like the following:

<span id="pg1" role="doc-pagebreak" aria-label="page 1">

EPUB 3 uses the epub:type attribute to identify the page list in the navigation document. The attribute is used on a nav element with the value "page-list" (note the different hyphenation). The ARIA role attribute has no effect unless the navigation document can be directly accessed by users (i.e., the document is in the EPUB spine). Like the previous HTML example, the contents of the nav element is a list of links to the page break locations.

<nav epub:type="page-list" role="doc-pagelist" aria-labelledby="pglist">
   <h2 id="pglist">Page List</h2>
   <ol>
      <li><a href="chapter01.xhtml#page001">1</a></li>
      <li><a href="chapter01.xhtml#page002">2</a></li>
      <li><a href="chapter01.xhtml#page003">3</a></li>
      …
   </ol>
   </nav>

The EPUB 2 and DAISY 3 formats both use an XML grammar called the NCX for expressing navigation aids. The page list is defined within the ncx element using the pageList tag. Each pageTarget within this element identifies a page break, providing both a label and a destination.

<ncx xmlns="http://www.daisy.org/z3986/2005/ncx/"
     version="2005-1"
     xml:lang="en-US">
   …
   <pageList>
      <pageTarget id="p1" type="normal" value="1">
         <navLabel><text>1</text></navLabel>
         <content src="content.html#p001"/>
      </pageTarget>
      <pageTarget id="p2" type="normal" value="2">
         <navLabel><text>2</text></navLabel>
         <content src="content.html#p002"/>
      </pageTarget>
   </pageList>
</ncx>

Tests

Procedure

  1. Check that a page list, or a link to a page list exists in the publication.
  2. Check that all the static page break locations in the publication are represented in the page list.
  3. Check that the entries in the page list link to the correct location in the publication.

Expected Results

  • #1, #2 and #3 are true.