Comments: User Interface Independence for accessible Rich Internet Applications

This submission, which antedates current work, suggests interfaces pertinent to
both IndieUI Events and User Contexts. Some aspects of the proposal are beyond
the scope of this working group, for instance the functions to access an
assistive technology cursor and to create speech output.

My initial comments concern the event-related aspect of the proposal. The
details of interfaces and event types will be developed in due course in
response to use cases. There are, however, wider issues to consider as well.

The proposal establishes the following behaviour for events that it defines:

1. An abstract user interface event is dispatched and may be handled by
registered listeners.

2. If it handles an abstract event successfully, the Web application calls
preventDefault() to suppress the default action.

3. Otherwise, the user-agent may dispatch the underlying device-specific
events (e.g., keyboard events).

Effectively, the Web application only receives the underlying device-specific
events if the associated abstract events are not cancelled and the UA happens
to forward the device-specific events.

The following alternative design would be more consistent with the DOM Level 3
Events specification, for example the relationship between mouseup, mousedown
and click events.

1. The UA assigns default actions to certain device-specific UI events and
event sequences; these actions dispatch the associated abstract events.

2. Consequently, the Web application receives both the device-specific events
corresponding to a user's interaction and the abstract events defined in
IndieUI events.

3. If a device-specific event is cancelled, then (per DOM Level 3 Events), the
default action, namely the dispatching of the associated abstract event, is not
performed.

4. If there is no device-specific event defined in the user-agent's API
corresponding to a user's input (for instance, no event associated with speech
input), then only the abstract event is dispatched.

There are trade-offs to be made in both designs, and these alternatives are
not exhausive. My purpose is merely to place the issues before the working
group.

I found it helpful in reviewing the submission that specific interfaces have
been put forward in the proposal. These will contribute to our work,
especially in connection with events.

Received on Thursday, 9 August 2012 05:30:43 UTC