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.
HTML and XHTML
This failure relates to:
This describes a failure condition for text alternatives for images that
should be ignored by AT. If there is no alt attribute at all assistive
technologies are not able to ignore the non-text content. The alt attribute
must be provided and have a null value (i.e., alt="" ) to avoid a failure of this Success Criterion.
This describes a failure condition for text alternatives for images that should be ignored by assistive technology (AT). If an image has the attribute role="presentation", it will be ignored by AT. However, if it does not have role="presentation", and if there is no alt attribute at all assistive technologies are not able to ignore the image. For decorative images which need to be ignored by AT, either role="presentation" must be used or the alt attribute must be provided and have a null value (i.e., alt="") to avoid a failure of this Success Criterion.
Decorative images that have no alt
attribute and no role attribute
No resources available for this technique.
(none currently listed)
For any img element that is used for purely decorative content:
Check whether the element has no role attribute or has a role attribute value that is not "presentation".
Check whether the element has no alt attribute or has an alt attribute with a value that is not null.
If step #1 is true and if step #2 is true, this failure condition applies and content fails the Success Criterion.