Sorry, it's API specific:
Table of document change scenarios and events to be fired in each API Scenario MSAA + UIA Express event MSAA + IAccessible2 event ATK/AT-SPI event Mac OS X Notification When text is removed EVENT_OBJECT_LIVEREGIONCHANGED IAccessible2: IA2_EVENT_TEXT_REMOVED text_changed::delete If in a live region, AXLiveRegionChanged When text is inserted EVENT_OBJECT_LIVEREGIONCHANGED IAccessible2: IA2_EVENT_TEXT_INSERTED text_changed::insert If in a live region, AXLiveRegionChanged When text is changed EVENT_OBJECT_LIVEREGIONCHANGED IAccessible2: IA2_EVENT_TEXT_REMOVE text_changed::delete If in a live region, AXLiveRegionChanged and IA2_EVENT_TEXT_INSERTED and text_changed::insert
aria-atomic
behavior is suggested:
User agents SHOULD check the chain of ancestor elements for aria-atomic="true". If found, user agents SHOULD set the RELATION_MEMBER_OF relation to point to the ancestor that sets aria-atomic="true".
aria-live
behavior is as well:
User agents SHOULD ensure that an assistive technology, running in process can receive notification of a node being removed prior to removal. This allows an assistive technology, such as a screen reader, to refer back to the corresponding DOM node being deleted. This is important for live regions where removals are important. For example, a screen reader would want to notify a user that another user has left a chat room. The event in MSAA would be EVENT_OBJECT_HIDE. For ATK/AT-SPI this would be children_changed::remove. And in Mac OS X, the event is AXLiveRegionChanged. This also requires the user agent to provide a unique ID in the accessibility API notification identifying the unique node being removed.
References
- WAI-ARIA 1.0 Authoring Practices: Managing Dynamic Changes
- Accelerated Dynamic Content Technical Style Guide
- WAI-ARIA 1.0 User Agent Implementation Guide: Changes to document content or node visibility
- WAI-ARIA 1.0 Implementation Report
- PDF Accessibility Notes
- WAI-ARIA References
- Protocols and Formats Working Group (PFWG) Test Harness