Techniques for WCAG 2.0

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ARIA10: Using aria-labelledby to provide a text alternative for non-text content

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.

Applicability

This technique applies to HTML with Accessible Rich Internet Applications (WAI-ARIA).

This technique relates to:

User Agent and Assistive Technology Support Notes

See User Agent Support Notes for ARIA10. Also see WAI-ARIA Technology Notes.

Description

The purpose of this technique is to provide a short description for an element that can be read by assistive technologies (AT) by using the aria-labelledby attribute. The aria-labelledby attribute associates an element with text that is visible elsewhere on the page by using an ID reference value that matches the ID attribute of the labeling element. Assistive technology such as screen readers use the text of the element identified by the value of the aria-labelledby attribute as the text alternative for the element with the attribute.

Examples

Example 1: Providing a short description for a complex graphic

This example shows how to use the aria-labelledby attribute to provide a short text description for a read-only complex graphic of an star rating pattern; the graphic is composed of several image elements. The text alternative for the graphic is the label, visible on the page beneath the star pattern.

<div role="img" aria-labelledby="star_id">
<img src="fullstar.png" alt=""/>
<img src="fullstar.png" alt=""/>
<img src="fullstar.png" alt=""/>
<img src="fullstar.png" alt=""/>
<img src="emptystar.png" alt=""/>
</div>

<div id="star_id">4 of 5</div>

Working example: Providing a short description for a complex graphic.

Resources

Resources are for information purposes only, no endorsement implied.

Tests

Procedure

  1. Examine each element where the aria-labelledby attribute is present and the element does not support the alt attribute.

  2. Check whether the value of the aria-labelledby attribute is the id of an element on the web page.

  3. Determine that the text of the element identified by the aria-labelledby attribute accurately labels the element, provides a description of its purpose, or provides equivalent information.

Expected Results

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.