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RE: Techniques for GL 4.2 L1 SC6

From: <Becky_Gibson@notesdev.ibm.com>
Date: Mon, 31 Oct 2005 15:06:12 -0500
To: w3c-wai-gl@w3.org
Message-ID: <OF5DE60F0F.DA6C6BFC-ON852570AB.006A0393-852570AB.006E9C7D@notesdev.ibm.com>

Regarding the techniques for GL 4.2 L1 SC6

I'm not sure what "Providing an event whenever a change to structure, 
selection, focus, attributes, values, state, or relationships occur. " 
means?  As a JavaScript programmer I generally respond to system events 
rather than providing them.  There is a DOM api, dispatchEvent(someEvent) 
which can be sent to a particular node. Do other technologies such has 
Flash have the concept of providing an event? 

I can see using DHTML Accessibility to satisfy some of this success 
criterion but even then, I'm not sure how to deal with focus?   I can 
programmatically set focus to an object by calling object.focus(). But, I 
have to first be using an object that can accept focus - either a form 
element or link or I have set the tabindex value on the object.   Is 
calling focus on an object considered programmatically determined since it 
is in the script?    The user agent has to do something with that method 
call (usually by generating a focus event).  As the programmer, I am 
relying on the user agent to generate the focus event for that object and 
the AT to acknowledge that focus.  Is a success criteria about that really 
necessary?  Maybe not for HTML but perhaps for other technologies? 

I have the same question about changing values?  In HTMLand JavaScript  I 
can programmatically change the value of an input type=text field. If I 
then set focus to the field, the AT should pick it up.  I'm not sure there 
are really any specific techniques for this.  If the call to 
inputObject.focus() is in the JavaScript code then isn't it automatically 
programmatically determined? 

Regarding the script technique:
Writing new content directly to the DOM  - while this is the preferred way 
to add new content, there is no guarantee that the AT's will pick it up. 
For example, if you add the new information at the top of the page and 
then do not set focus to it, the AT user may never know the information 
has been added. But, if focus is set the change in focus may be unexpected 
and you could be violating GL 3.2 L1 SC1 or L3 SC2. 

Also, using document.write is listed as a common failure. While my advice 
is to create objects via the DOM,  when done right, document.write can be 
identified by AT.  I generally don't recommend document.write because it 
is not useable in XHTML and thus code will have to eventually be rewritten 
if migrating from HTML to XHTML. So, perhaps it can stay as a common 
failure but the reasons need to be identified.

I'm not at all sure I see the need for this success criterion.  Is the 
focus really more on future technologies?  It still seems like we are 
specifying requirements on the user agent rather than the web content.

my two cents,

Becky Gibson
Web Accessibility Architect
IBM Emerging Internet Technologies
5 Technology Park Drive
Westford, MA 01886
Voice: 978 399-6101; t/l 333-6101
Email: gibsonb@us.ibm.com
Received on Monday, 31 October 2005 20:06:21 UTC

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