Live region properties vs announcement notification

[cookiecrook]

We had discussed using a refined announcement notification (in Phase 2?) to avoid some of the problems with live regions. Let's put in a placeholder for the notification (e.g. "speak this text") and remove the aliases for live, relevant, atomic, etc.

Authors wanting to use live regions can still implement them via DOM methods like setAttribute, so we're not losing anything by not including the aliases on accessibleNode.

(Spawned from discussion in Issue #78)

[alice]

Proposal from @cookiecrook: allow sending a payload including notification, urgency, callback... etc?

• Some global object like Navigator which handles requests
• Have a queue object which allows managing posted notifications?
• Allow polyfilling live regions?
• But not require a context element

Counter-proposal:

el.accessibleNode.announce("New content loaded", AccessibleNode.POLITE);

• context element is required, but may be root node
• no queue object (at least initially)