This module will focus on testing a page to ensure that Text Equivalents are associated with all relevant non-text elements in a web page.
The Section 508 requirement covering this is: §1194.22 (a) A text equivalent for every non-text element shall be provided (e.g., via "alt", "longdesc", or in element content).
When a graphic is used with the intent to convey information to users, alternative text should also be provided in order to convey equivalent information to users of assistive technology. All meaningful images that contribute understanding to the surrounding content must have alternative text. If an image is not meaningful, like a spacer image, an empty alt attribute should be used such as alt="".
What is meant by the term, non-text element?
- Audio clip
- Feature that conveys meaning through a picture or sound, examples:
- Toolbar buttons that only contain an image as content
- Charts and graphs
- Streaming audio or video
How should audio presentations be treated?
- Simply put, audio content should also have a transcript available for persons to view.
- There is a specific requirement for multimedia standards (§1194.22 (b)) which addresses the majority of questions and concerns surrounding accessibility of audio content. These standards reside as a separate module.
What are ways of assigning text to elements?
- Provide text that describes an image in the alt attribute of the <img> tag
- Java - include the alternative text between opening and closing <applet> or <object> tags
- Include textual description in the page in the surrounding context, example:
Remember, both testers and developers can use the checkpoints for this requirement to be sure the products they are working with will be accessible to users of Assistive Technology (AT).
Use the link above to look at the checkpoints now. You may wish to keep the window open as a reference to use as you complete this module.
Video Overview of this Requirement
To view an approximately two-minute video with additional information which may be helpful to testers and developers, select the video link below. The video will open in a new window; if you are using a screen reader to take this training, press enter when you hear, "To start, press Play button."
Alternative text should be brief and should not duplicate information provided on the page other than to make the intent and content of the image available to users of assistive technology. We recommend using a few words and not exceeding 150 characters in the alt attribute. If you must say more about a complex image, use a long description through a longdesc attribute or describe the image in the surrounding text to provide the necessary information.
Long descriptions give screen reader users the ability to access a file with the description that will not impact a sighted user’s graphical view of the page. It should be noted that the longdesc attribute does not create nor should a link be created to the long description file. The longdesc attribute serves screen reader users specifically.
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