2.11 Common issues: Dynamic content equivalents
From the Becta document
This requirement is directly linked to Checkpoint 1.1 - which requires that every non-text element of a page has a text equivalent. If the site contains content that is regularly updated (for instance in a Java Applet that draws information from a database) then the text equivalents must be updated at the same time so that people who are not able to access the dynamic content (in the example of the Java Applet above those who do not have Java supported in their browser) can still access the relevant information.
Frames are another method, often used to present dynamic content. Frames are used to divide the page into sections. For example, the left hand side of a web page could present navigation links in one frame (the navigation frame), while the main content is presented in another (the content frame). The navigation frame always presents the same content but the information in the content frame is dynamic because it changes depending on the link selected from the navigation frame. The user will need to be informed that the content on the content frame has been updated.
A simple solution to this requirement is to use the object element. The object element allows you to embed content so that if the original object is not supported then the embedded content is used instead. You can nest several different layers of alternatives - if information is being presented in a Java Applet, then you may consider having a video alternative in case Java is not supported, and in case neither Java nor video is supported then you need to have a text equivalent as well
<object classid="java:News.class" width="500" height="300">
<object data="news.mpeg" type="video/mpeg">
<li><a href="news1.html">News 1</a>.</li>
<li><a href="news2.html">News 2</a>.</li>
<li><a href="news3.html">News 3</a>.</li>
6.2 Ensure that equivalents for dynamic content are updated when the dynamic content changes. [NGfL requirement]
Read the following WAI recommendations to help ensure that your site meets this requirement: