RE: ARIA should require DOM mutation event support for compliance.

Rich,

You said:

There needs to be some formal way for the AT to register and be notified of
document mutation events whether they are through the DOM API or not. There
are platform accessibility API that can be used to allow the AT to listen
for these types of change events and not necessarily by accessing the DOM.



UAAG20 currently has the following success criteria [1] related to
programmatic access by other technologies. Do they cover 'notification of
documentation mutation events?' If not, is a new criteria needed (please
provide proposed language)? Or, is the 'notification' assumed and
elaboration should be provided in the techniques document?

 

2.1.1 Accessibility Platform Architecture: Support an
<http://www.w3.org/WAI/UA/2008/WD-UAAG20-20081210/WD-UAAG20-20081210#def-acc
ess-platform-arch> accessibility platform architecture relevant to the
platform.

2.1.2 Name, Role, State, Value, Description: For all user interface
components including the user interface and rendered content, make available
the name, role, state, value, and description via an accessibility platform
architecture.

2.1.3 Accessible Alternative: If a feature is not supported by the
accessibility architecture(s), provide an equivalent feature that does
support the accessibility architecture(s). Document the equivalent feature
in the conformance claim.

2.1.4 Programmatic Availability of DOMs: If the user agent implements one or
more DOMs, they must be made programmatically available to assistive
technologies.

2.1.5 Write Access: If the user can modify the state or value of a piece of
content through the
<http://www.w3.org/WAI/UA/2008/WD-UAAG20-20081210/WD-UAAG20-20081210#def-use
r-interface> user interface (e.g., by checking a box or editing a text
area), the same degree of write access is available programmatically.

2.1.6 Properties: If any of the following properties are supported by the
accessibility platform architecture, make the properties available to the
accessibility platform architecture:

.        (a) the bounding dimensions and coordinates of rendered graphical
objects

.        (b) font family of text

.        (c) font size of text

.        (d) foreground color of text

.        (e) background color of text.

.        (f) change state/value notifications

2.1.7 Timely Communication: For APIs implemented to satisfy the requirements
of this document, ensure that programmatic exchanges proceed at a rate such
that users do not perceive a delay.   (Level AA).

 

[1]
http://www.w3.org/WAI/UA/2008/WD-UAAG20-20081210/WD-UAAG20-20081210#principl
e-perceivable

 

 

Jim Allan

 

From: wai-xtech-request@w3.org [mailto:wai-xtech-request@w3.org] On Behalf
Of Richard Schwerdtfeger
Sent: Wednesday, December 17, 2008 4:08 PM
To: Boris Zbarsky
Cc: Aaron M Leventhal; Joseph Scheuhammer; wai-xtech@w3.org;
wai-xtech-request@w3.org
Subject: Re: ARIA should require DOM mutation event support for compliance.

 

Boris, 

The AT needs to be able to know when parts of the document change to support
live regions as well. There needs to be some formal way for the AT to
register and be notified of document mutation events whether they are
through the DOM API or not. There are platform accessibility API that can be
used to allow the AT to listen for these types of change events and not
necessarily by accessing the DOM.

I don't believe this belongs in the ARIA specification but rather the user
agent implementers guide. 


Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist
blog: http://www.ibm.com/developerworks/blogs/page/schwer

Inactive hide details for Boris Zbarsky ---12/09/2008 03:52:48 PM---Joseph
Scheuhammer wrote:Boris Zbarsky ---12/09/2008 03:52:48 PM---Joseph
Scheuhammer wrote:


Boris Zbarsky <bzbarsky@MIT.EDU> 
Sent by: wai-xtech-request@w3.org 

12/09/2008 03:46 PM




To


Joseph Scheuhammer <clown@utoronto.ca>




cc


Aaron M Leventhal/Cambridge/IBM@IBMUS, wai-xtech@w3.org,
wai-xtech-request@w3.org




Subject


Re: ARIA should require DOM mutation event support for compliance.

 








Joseph Scheuhammer wrote:
> Webapp scripts are written to listen for various events, and handle as 
> appropriate.  Having to also poll for changes that an external agent may 
> or may not make is not an option.

Sure.

>> Even more alternately, authors could ignore the SHOULD-level requirement.

> Even if they do, the possibility remains that ATs might change aria-* 
> attributes, and the scripts need to handle this.

Agreed.  Just saying that this doesn't mean that a UA can't 
ARIA-compliant without implementing mutation events.

-Boris