Assistive technologies, such as speech recognition systems and alternate input devices for users with mobility impairments, require the ability to control a web application in a device-independent way. WAI-ARIA states and properties reflect the current state of rich internet application components. The ability for assistive technologies to notify web applications of necessary changes is essential because it allows these alternative input solutions to control an application without being dependent on the standard input device which the user is unable to effectively control directly.
User agents MUST provide a method to notify the web application when a change occurs to states or properties in the system accessibility API. Likewise, web application authors SHOULD update the web application accordingly when notified of a change request from the user agent or assistive technology.
-Many state and properties can be changed by assistive technologies through existing accessibility APIs by responding to a default action event. For example, the