Checkpoint (L) focuses on utilizing scripting languages to display content, or to create interface elements. The information provided by the script shall be identified with functional text that can be read by assistive technology.
Web page authors have a responsibility to provide script information in a fashion that can be read by assistive technology. When authors do not put functional text with a script, a screen reader will often read the content of the script itself in a meaningless jumble of numbers and letters. Although this jumble is text, it cannot be interpreted or used.
Example - Using Functions Correctly
This type of link, as written, presents tremendous accessibility problems, but those problems can easily be remedied. The <a> tag, of course, supports the "alt" attribute that can also be used to describe the image and the effect of clicking on the link. Thus, the following revision remedies the accessibility problems created in the previous example:
Another technique advocated by some developers is to use the "title" attribute of the <a> tag. For instance, the following example includes a meaningful description in a "title" attribute:
Note: This tag is supported by some but not all assistive technologies. Therefore, while it is part of the HTML 4.0 specifications, authors should use the "alt" tag in the enclosed image.
For instance, the following link will replace the content in the status line with a custom message "Nice Choice".
Use the NOSCRIPT element to describe the action or replace the functionality of any scripts you embed in your page.
If you write a SCRIPT that animates a comic strip by presenting a new panel whenever the user mouse-clicks or presses a key, then use the NOSCRIPT element to provide a text alternative that describe the entire comic strip.
... script to display and replace each frame of the comic strip as requested by a user event ...
In the first panel, Lucy is holding the football. In the second panel, Charlie Brown is seen charging towards the football. And so on..."
This page adopted from the Access Board 508.