Errata for EPUB Content Documents 3.0.1

2.1.3.7. The aria-describedat Attribute

The aria-describedat attribute was added to EPUB 3.0.1 to provide a mechanism for associating external descriptions with images, tables and other complex content. The attribute was included in early drafts ARIA 1.1, but has subsequently been removed due to objections and will not be reintroduced in the future. Without a formal definition, the attribute will not be valid in HTML5 content and will not be supported by assistive technologies.

As a result, authors of EPUB Publications are strongly urged not to use this attribute to associate descriptions. The attribute can only be deprecated from EPUB 3.0.1 since it is already a formal specification, but it will be permanently removed in the next revision.

Authors are encouraged to use other web-compliant methods for associating external descriptions, such as hyperlinks to non-linear content documents and using aria-describedby to point to a hidden iframe element that references the description.

Other web-friendly alternatives not currently available in EPUB 3, such as the longdesc attribute and details element, will be considered in the next revision.