W3C home > Mailing lists > Public > w3c-wai-ua@w3.org > January to March 1999

Re: Issues

From: mark novak <menovak@facstaff.wisc.edu>
Date: Mon, 29 Mar 1999 18:35:59 -0500
Message-Id: <v03007809b325bcfc6685@[]>
To: schwer@us.ibm.com, w3c-wai-ua@w3.org
just wanted to add a few thoughts....

At 6:01 PM -0500 3/29/99, schwer@us.ibm.com wrote:
>After reviewing the documents Jon referenced, I believe that there are some
>issues we need to consider based on an action item I am working on with
>Mark Novak for the PF group:
>   We have to be careful of what we put in the DOM and do not put in the
>   DOM. What I feel is needed is an interface that extends the DOM for a
>   user agent. This way we can preserve the existing DOM for some of its
>   intended purposes such as servlet processing of HTML pages where user
>   interface issues are not of consideration.

>   We need to create an AccessibleObjectModel which extends the DOM to
>   application components. The DOM provides some key features that we can
>   reuse namely an architected event model, a range model, an iterator, CSS
>   to node mapping, and a tree structure.

The things Rich is referring to here, are proposed in DOM Level 2.  I'd prefer
to not call this new object model anything using the word "accessible", since
I believe the potential scope is much larger (e.g., automated testing tools,
validation tools, search engines, etc.).

>   The new AccessibleObjectModel needs to be designed such that each
>   document node can be constructed by a mapping of XML semantic schemas
>   into each individual node.

If individual nodes maps to individual elements (??), then we may also need
a grouping and un-grouping semantic mapping as well.

>   Position information is not important for all assistive technologies if
>   we can provide accessible action sets for specific node types as
>   specified by its schema. Screen reader technology may be interested in
>   position information when it needs to determine where line breaks in
>   text occur or if they need to map objects to an OSM representation. The
>   need for mapping to an OSM representation should be less important with
>   true object model technology. Position information is very relevant to
>   screen magnifiers that will use the caret or selector position to pan
>   the magnification point to the users point of focus. Position
>   information should not be stored in the core DOM because there it has no
>   meaning in a non-visual orientation. This again is why we need to create
>   a new AccessibleObjectModel that inherits from the DOM to provide this
>   feature.

>   Keyboard bindings could be specified for specify node types based on the
>   schema. Although it would be up to the authoring tool and/or browser to
>   define these, we will need to establish a set of key binding for
>   specific node types that will not conflict with different operating
>   system specific key bindings for obvious reasons. This is something we
>   had to deal with for Java.

I think these would also be in the ??? object model that extends DOM,
not DOM itself?

>   On the issue of using standard rather than custom controls when
>   designing user agents, the accessible object model should define an
>   interface that can be applied to application object model components.
>   The interface will provide the necessary information to access a
>   particular object model component based on the specified XML schema. On
>   some systems like UNIX with the X Windows System, these components may
>   be part of someone's widget set. Allowing the browser (one user agent
>   example) to map the proper semantic information to that component or
>   node allows the user agent to use whatever widget set they like and
>   still be accessible. Bottom line: The restriction to use standard
>   controls is an unnecessary restriction if we design the Accessibility
>   interface properly.

>   Regarding the issue of "Allowing the user to turn on and off support for
>   spawned windows" We need to develop and AccessibleApplication interface
>   that can be implemented by a user agent so that an assistive technology
>   can be notified when a spawned document has focus. This is again
>   separate from the DOM.
>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.",
Received on Monday, 29 March 1999 19:40:29 UTC

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