Web applications today are a challenge to make accessible because native HTML does not have the language to support all of the types of widgets added to Web pages. WAI-ARIA provides a way to add roles, states and properties to make RIA accessible to assistive technology such as screen readers.
Web Design Posts
The web is a visual medium, which is a great way to convey information…unless you’re blind. An image, or other visual content, is only informative if users can see it. So making images perceivable is one of the most important ways to make websites accessible.