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RE: RESOLUTION: Table access checkpoints for Desktop Graphical User Agents

From: Charles Oppermann <chuckop@MICROSOFT.com>
Date: Thu, 28 Jan 1999 14:53:22 -0800
Message-ID: <BB61526CDE70D2119D0F00805FBECA2F054EA428@RED-MSG-55>
To: w3c-wai-ua@w3.org
<<
I am concerned that systems don't support an exposed DOM. The purpose of the
DOM is to provide a cross-platform template which can enable assistive
technologies to quickly provide access to different browsers our document
presentation tools. 
>>

Actually, the goal of the DOM specification is to define a programmatic
interface for XML and HTML.    I don't believe it addresses the needs of
external clients or assitive technology.  A known limitation of DOM level 1
is access control and it doesn't appear to be addressed yet in DOM level 2.

<<
Full support for an accessible DOM interface would make it easier for
products like the IBM Home Page Reader to rapidly build support for various
web browsers/ document viewers on a broad host of applications, machines,
and environments.
>>

DOM is perfect for things like Home Page Reader!  If Home Page Reader was
implemented using the Internet Explorer Web Browser control, it would have
complete access to the Dynamic HTML object model and could play with it all
it wanted to (with the associated risks of breaking scripts).

I believe that this is what CAST and The Productivity Works are doing with
their products.

The problem is getting access and manipulating someone else's DOM.
Accessing an object model out of the address space of an existing browser
presents performance, reliability and security concerns that have not yet
been addressed.

For example, if I hack on the object model of a page downloaded from the web
and convert all the table objects to something else, the script provided by
the author of the page may break when it expects to access a table object
and find none.

I think providing the HTML object model in a read-only fashion is a great
idea - but it just hasn't been addressed yet.


-----Original Message-----
From: schwer@us.ibm.com [mailto:schwer@us.ibm.com]
Sent: Thursday, January 28, 1999 9:23 AM
To: Charles Oppermann
Cc: Jon Gunderson; w3c-wai-ua@w3.org
Subject: RE: RESOLUTION: Table access checkpoints for Desktop Graphical
User Agents





Chuck,

I am concerned that systems don't support an exposed DOM. The purpose of
the DOM is to provide a cross-platform template which can enable assistive
technologies to quickly provide access to different browsers our document
presentation tools. While I applaud all the work Microsoft has done on MSAA
I would strongly advocate the track taken by the W3C which requires a
platform independent DOM specification and apply accessibility requirements
to it.

There will be cases where hand held devices will not provide MSAA and
standard needs to be followed to quickly provide access to that document.

We cannot achieve direct accessibility if we do not adhere to
cross-platform standards.

Full support for an accessible DOM interface would make it easier for
products like the IBM Home Page Reader to rapidly build support for various
web browsers/ document viewers on a broad host of applications, machines,
and environments.

I will admit that the DOM interface needs some work to support
accessibility and my team is looking those issues. One example is a
requirement that the DOM implementation to be re-entrant to allow assistive
technologies to access the DOM without the fear of creating deadlock
situations. I have not yet found this in the DOM specification, although it
may be there.

Rich



Rich Schwerdtfeger
Lead Architect, IBM Special Needs Systems
EMail/web: schwer@us.ibm.com http://www.austin.ibm.com/sns/rich.htm

"Two roads diverged in a wood, and I -
I took the one less traveled by, and that has made all the difference.",
Frost



Charles Oppermann <chuckop@microsoft.com> on 01/27/99 06:36:21 PM

To:   Jon Gunderson <jongund@staff.uiuc.edu>, w3c-wai-ua@w3.org
cc:    (bcc: Richard Schwerdtfeger/Austin/IBM)
Subject:  RE: RESOLUTION: Table access checkpoints for Desktop Graphical
          User Agents





FYI - I'm evaluating the feasibility of making the DOM (or more
specifically, Microsoft Dynamic HTML Object Model) a public interface.

As I said in the previous teleconference, current methods of accessing the
internal object model are unsupported.

I'm worried about this proposal since it would
(a) force browser manufactures to follow DOM
(b) force browser manufactures to expose DOM directly.  Currently Internet
Explorer supports Active Accessibility, which provides some DOM-like
information, tailored to the needs or accessibility aids.

As soon I have more information, I'll pass it on.

Charles Oppermann
Program Manager, Accessibility and Disabilities Group, Microsoft
Corporation
mailto:chuckop@microsoft.com  http://www.microsoft.com/enable/
"A computer on every desk and in every home, usable by everyone!"

-----Original Message-----
From: Jon Gunderson [mailto:jongund@staff.uiuc.edu]
Sent: Wednesday, January 27, 1999 3:12 PM
To: w3c-wai-ua@w3.org
Subject: RESOLUTION: Table access checkpoints for Desktop Graphical User
Agents


Tables Issue Resolution for Desktop Graphical User Agents
The solution strategy for Desktop Graphical User Agents for making tables
more
accessible is for user agents to implement the Document Object Model (DOM)
and
provide an interface for assistive technology to access DOM.  Assistive
technology therefore would have direct access to table information for
alternaive rendering in speech, Braille or enlarged text.

Advantages to DOM approach
1. Assistive technology has direct access to element information and is not
dependent on any filtering of information that occurs during graphical
rendering of information.
2. W3C recommendations exist for specifying implementation and conformance

Potential Disadvantage of DOM approach
1. Technique needs to gain acceptance by assistive technology developers.
So
far this has not been a problem since Henter-Joyce, Productivity Works and
Alva
participants are either already using DOM or are interested in its
capabilities.

Primary checkpoints for Desktop Graphical User Agents to implement
1. Implement DOM level 1
2. Expose DOM level 1 to assistive technologies

Checkpoint under consideration and refinement
1. Provide a means for the user to add accessibility functionality or
change
the rendering of a document using the scripting capabilities of the user
agent

Issues related to this checkpoint
1. Intent is provide some way for user to adjust rendering or add
functionality
for legacy assistive technology by using scripting tools already available
in
many desktop graphical user agent technologies.
2. This is not a good checkpoint since it is too specific, but could be a
technique for a more general checkpoint.
3. This may be a good checkpoint if it was more general, but if it was more
general it could probably be defined as an asssitive technology.  It
therefore
would not need to exist.
4. There is a DOM2 working group defining user side scripting capability,
need
to coordinate with that group and see how this issue relates to the work of
that group.

Checkpoints related to native table linearization by desktop graphical user
agents have been rejected based on the following information.

Potetential Advantage of Linearization Approach
1. Current screen reader users would have somewhat better access to table
information, but it is not a complete solution.  Users would still need to
wait
for it to be implemented before they could benefit from the feature.

Problems with linearization approach
1. Linearization is only one of many techniques in solving the table access
problem, it doesn't meet the requirement for checkpoints stating a general
user
problem. It could be included as a technique in the technique document.
2. It doesn't provide a path for innovation in solving table access issues
and
will become outdated as technology improves.
3. Navigation and rendering are needed for a complete solution, which
complicates the desktop graphical browser issue.
4. None of the assistive technology vendors currently involved in the group
have requested the inclusion of this feature.  Their interest seems to be
more
in the area of DOM or accessibility APIs for access to tables.
5. Mainstream browser developers have indicated that this feature is
technically difficult to implement.  It would take a long time for user
agent
developers to implement and therefore maybe obsolete before users would be
able
to benefit from the technique.

If you have additional information that would change or extend this
resoution
please send it to the list as soon as possible for consideration by the
group.

Jon
Chair UA working group






Jon Gunderson, Ph.D., ATP
Coordinator of Assistive Communication and Information Technology
Division of Rehabilitation - Education Services
University of Illinois at Urbana/Champaign
1207 S. Oak Street
Champaign, IL 61820

Voice: 217-244-5870
Fax: 217-333-0248
E-mail: jongund@uiuc.edu
WWW: http://www.staff.uiuc.edu/~jongund
     http://www.als.uiuc.edu/InfoTechAccess
Received on Thursday, 28 January 1999 17:53:30 UTC

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