Monday, May 12, 2008
Accessible Rich Internet Applications
byFollowing the enormous growth of Ajax powered rich internet applications like Google Maps there has been much concern about accessibility and the need–in many cases–to ensure fully accessible content for users with assistive technologies such as screen readers and screen magnifiers. A solution to these inaccessibility problems called ARIA (Accessible Rich Internet Applications) is currently being developed and standardized. ARIA has been implemented in some Web browsers such as Firefox 1.5 and above to permit communication between assistive technologies and accessibility APIs like Apple’s Universal Access. Soon, ARIA will be available in Web development toolkits such as an upcoming version of the jQuery library for Web authors to easily develop or reuse accessible JavaScript widgets like tree-views and menu bars.
One example of an accessibility issue regarding the use of an assistive technology such as a screen reader is found in the manner in which they read a Web document. Screen readers dictate in a linear fashion, from the title of the page, through each navigation item (if not skipped), main content and to the footer. In an Ajax application, a user sends a request by clicking on a link which then will return a response from the server in the background. The response is then used to update content on the page in a particular order within the structure of the (HTML) document without a browser refresh and without the assistive technology starting back at the top of the document or reading the user the newly placed content. This will leave some disabled users with less than a rich Internet experience.
A long-term solution to some accessibility issues regarding JavaScript widgets–like the ones mentioned above–is the coming of new features in HTML 5 such as additional elements and attributes that will give more meaning to the structure of a Web document and the type of content presented. The time until HTML 5 becomes ubiquitous is quite a ways out, but the good news is that ARIA provides Web authors with technologies to map controls, Ajax live regions, and events to accessibility application programming interfaces right now.
