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September 16, 2005
AJAX Access
Pete at standards-schmandards.com put together a post on AJAX and accessibility and an example back in March, but it has attracted some attention on WebAIM discussion list. Pete's example is a useful one, but there are obviously limits to how far this model can be extended. On an web application to book a flight there are more bits of information than can be easily communicated in alert dialogs, and if the user needs to interact with the new information in a dialog, additional difficulties present. Still, a useful technique to keep in the back pocket, and use when appropriate.
It is and will continue to be very interesting to see how screen readers and web developers handle increasingly dynamic content. The issues that we've dealt with in "traditional" web accessibility have been largely providing equivalents, associations, and structure, but with AJAX content the importance of notification is amplified. When developing content, we need to ask whether a user who is unable to view the entire screen will know if a change has occurred on the page and if so, whether it is reasonable to expect that he will know where on the page that change occurred. You might be able to expect that a screen reader user will run into a piece of changed content if the change takes place immediately downstream of the point of interaction, but changing content at the top of the page with a link halfway down the page, or even right above the interaction point, is problematic for many users.
Whether dynamically changing elements trigger a full, partial, or no screen update for the screen reader is up to the screen reader developers. Some types of page changes make this happen, some don't. A huge problem for AJAX, this is also arguably the toughest challenge in accessible Flash development. If you are interested in what is difficult, possible, or hopeful in accessible AJAX development, take a look at accessible Flash – there are strong parallels.
Posted by akirkpatrick at 08:33 AM | Comments (8)