This technique is not referenced from any Understanding document.
It is better for all objects on a page to conform, but there are certain circumstances where that may not be possible. There may be situations when an object or section of content targets people with certain disabilities while those same attributes make it inaccessible for someone else. There may also be other reasons not to have a conforming object on the Web page. When an object does not conform, then a link to a conforming alternate version is adjacent to the non-conforming object in the linear reading order or is associated with the the non-conforming content. The conforming alternate version conveys the same information as the non-conforming version.
Example 1: A video of a rap song where audio descriptions would interfere with the artistic integrity of the music
A video of a rap song named "The Hip Hop Kid" has a musical background. Introducing "Audio Description" speaking parts during the pauses in the song would interfere with the guitar lines and drum grooves that the artist is trying to convey. On the Web page, immediately following the video object, there is a link that says, "Audio described version of 'The hip hop kid'" which contains a version of the video containing audio descriptions of what is happening visually in the video.
Example 2: An image of a historical document
A Web page about the Declaration of Independence contains an image of the document. There is not sufficient contrast between the text and the background, and the handwriting on the document is difficult to read. A link takes the user to an HTML version of the document.
Example 3: An animation that is not accessibility supported
An interactive animation created using a Web technology that is not accessibility supported is displayed on a Web page. A link to a conforming alternate version of the animation is adjacent to the non-conforming content.
For each non-conforming object in a page:
- Check to see if there is a non-conforming object on the Web Page.
- Check to see if there is a link to an identifiable conforming version of the object directly after the non-conforming object in the linear reading order.
- Check to see if the link goes to a conforming version.
- Checks #2 and #3 are true.