Techniques for WCAG 2.0

Skip to Content (Press Enter)


F62: Failure of Success Criterion 1.3.1 and 4.1.1 due to insufficient information in DOM to determine specific relationships in XML

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 2.0 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 2.0.


Applies to the Document Object Model (DOM) for XML.

This failure relates to:


The objective of this technique is to ensure that Web pages can be interpreted consistently by user agents, including assistive technology. If specific relationships in a Web page are ambiguous, different user agents, including assistive technologies, could present different information to their users. Users of assistive technology, for example, may have different information presented to them than users of other mainstream user agents. Some elements and attributes in markup languages are required to have unique values, and if this requirement is not honored, the result can be irregular or not uniquely resolvable content.


Failure Example 1

  • An id attribute value that is not unique.

  • An SVG document uses id attributes on title elements (for alternative text) in order to reuse in other locations in the document. However, one of the title elements has an id that is also used elsewhere in the document, so the document is ambiguous.


Resources are for information purposes only, no endorsement implied.

(none currently listed)



  1. Check that elements or attributes that refer to unique identifiers inside the same document have a corresponding id value.

Note that for XML document types defined by a DTD, this refers to attributes of type ID, IDREF or IDREFS. For XML document types defined by a W3C XML Schema, this refers to elements or attributes of type ID, IDREF or IDREFS. (For compatibility, the types ID, IDREF and IDREFS should only be used on attributes, but using them for elements is possible, according to XML Schema Part 2: Datatypes Second Edition.) For other schema languages, check the corresponding mechanisms for specifying IDs and references to IDs.

Expected Results