AJAX and Accessibility

Accessibility in this section is used to describe making a web page friendly to screen reader software for users with vision impairments. Accessibility is a challenge with traditional web applications and becomes even more complicated with asynchronous updates. The strictest guidelines dictate no use of JavaScript whatsoever, which rules out everything shown so far in this chapter. Much of ASP.NET 2.0 relies on JavaScript for initiating postbacks. Given those caveats, there are some practical considerations that make for an accessible user experience.

The JAWS screen reader seems to be the most popular and works well despite the use of JavaScript. And appropriate use of column headers and labels works well to make sites accessible. But when you start updating portions of the screen asynchronously, you need to look at ways to let the screen reader know what has happened. One approach commonly used for accessibility is to use an iframe within a page where dynamic updates are occurring. Navigating the iframe itself is detected by screen readers so you can assert more control over what content updates are obvious. It is not a perfect solution as it returns the flash and flicker.