Guideline 8. Ensure direct accessibility of embedded user interfaces.
Ensure that the user interface follows principles of accessible design: device-independent access to functionality, keyboard operability, self-voicing, etc.
When an embedded object has its “own interface”, the interface — like the interface to the browser itself — must be accessible. If the interface of the embedded object cannot be made accessible, an alternative accessible solution must be provided.
Note. For information about accessible interfaces, please consult the User Agent Accessibility Guidelines ([WAI-USERAGENT]) and the Authoring Tool Accessibility Guidelines ([WAI-AUTOOL]).
8.1 Make programmatic elements such as scripts and applets directly accessible or compatible with assistive technologies [Priority 1 if functionality is important and not presented elsewhere, otherwise Priority 2.]
Refer also to Guideline 6.