Use case: Events / actions from accessibility clients

[minorninth]

One of the major gaps in ARIA is that a custom control can't be manipulated via accessibility actions.

For example, on almost all platforms, a native HTML slider can be modified by AT, typically some sort of setValue action. The browser receives the setValue on the accessible element and modifies the HTML control directly.

An ARIA slider doesn't work that way:

If AT or an automation client tries to call setValue on this object, nothing happens.

A scripting API for web accessibility could address this gap, allowing the web author to respond to these actions directly.