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Re: [Action] Issue 443: Repair of device-dependent author-specified behavior.

From: Jon Gunderson <jongund@uiuc.edu>
Date: Wed, 21 Feb 2001 18:52:20 -0600
Message-Id: <4.3.1.2.20010221185056.0322eda0@staff.uiuc.edu>
To: Ian Jacobs <ij@w3.org>, w3c-wai-ua@w3.org
Ian,
I like the reasoning behind the proposal.  I agree that the repair we have 
talked about has dubious guarantees of making content accessible.  What do 
other people think of the proposal?

Jon


At 01:40 PM 2/21/2001 -0500, Ian Jacobs wrote:
>Hello,
>
>Per my action item assigned at the 15 February 2001
>teleconference [1] about issue 443 [2], please consider this
>proposal for which device-dependent repair requirements should
>appear in UAAG 1.0.
>
>Checkpoint 1.1 of the 26 January 2001 Guidelines [3] states:
>
>    "Ensure that the user can operate the user agent fully through
>    keyboard input alone, pointing device input alone, and voice
>    input alone. [Priority 1]"
>
>I propose splitting this checkpoint in three (rough wording
>here):
>
>   Checkpoint A: "Ensure that the user can operate the user agent's
>   native functionalities through keyboard input alone, pointing
>   device input alone, and voice input alone. [Priority 1]"
>
>   Checkpoint B: "Ensure that the user can operate
>   device-independent functionalities specified in content through
>   keyboard input alone, pointing device input alone, and voice
>   input alone. [Priority 1]"
>
>   Checkpoint C: "Allow configuration so that the user can operate
>   device-dependent functionalities specified in content through
>   other devices (e.g., simulate pointing device specific behavior
>   through the keyboard). In this configuration, alert the user when
>   an active element has device-specific behaviors associated.
>   [Priority 3]"
>
>I think that checkpoint C should be Priority 3 because it is
>likely to provide incomplete repair. Thus, it clearly does not
>qualify for P1 by definition:
>
>    "This checkpoint must be satisfied by user agents, otherwise
>    one or more groups of users with disabilities will find it
>    impossible to access the Web."
>
>There is no guarantee that if satisfied, checkpoint C will make
>access possible. [I would also note that our priority statements
>don't say anything about the responsibilities of other
>parties. This is clearly an authoring issue first.]
>
>Consider these scenarios:
>
>1) The author has created content that is device independent. In
>this case, checkpoint B applies.
>
>2) The author has created content that is device-dependent, but
>has also provided alternative content (per WCAG 1.0 checkpoints
>9.2 and 11.4). In this case, emulation is not required since the
>author has ensured access.
>
>3) The author has created content that is device-dependent, and
>has not provided an alternative. The device-dependent content is
>either:
>
>   a) Content that doesn't really depend on a particular device
>      but has just been encoded that way, or
>
>   b) Content that really does depend on a particular device
>      (e.g., a user interface where the user scratches the
>      "silver paint" on an electronic lottery ticket to
>       reveal a hidden number).
>
>The user agent can't recognize the difference in general, since
>handlers are built with scripts. So that means that, in general,
>the user agent is not likely to repair any better content of type
>(3a) over content of type (3b).
>
>Repair in case (3a) is probably useful to some users, can be
>carried out automatically, and is technically feasible (e.g., the
>UA could throw an "onmouseover" event whenever an "onfocus" event
>occurs, or implement a "zap-mouse-to-focus" functionality).
>
>However, in case (3b), emulation is not likely to help some
>users.  Even a tool such as MouseKeys will not help some users
>(e.g., users who are blind) interact with the user interface. If
>the author has designed content that expressly takes advantage of
>the nature of two-dimensional visual space, there's not much
>users who are blind can do with certainty. Worse, emulating mouse
>events might cause unexpected behavior to occur, thus
>disorienting the user.  And, emulation of certain pointing device
>events is less obvious (e.g., how do you translate "onmousemove"
>to the keyboard?), so repair by the UA would likely be incomplete
>on this axis as well.
>
>In our current definition of "active element", we don't expect
>the user agent to recognize (and thus repair) the class of
>author-specified behaviors that are encoded through "event
>bubbling" techniques.
>
>Finally, the user agent should not be required to emulate
>mouse-specific behaviors that are not controlled by the user
>agent (e.g., the case of server-side image maps).
>
>----------
>CONCLUSION
>----------
>
>- Emulation of author-supplied device-specific behaviors seems to
>be useful for some cases, and not helpful (or even disorienting)
>in others.
>
>- The user agent is not expected to recognize the useful cases
>from the non-useful cases since behaviors are encoded through
>scripts today. This means that the user agent couldn't "warn" the
>user, for example.
>
>- Repair functionalities are likely to be incomplete and not
>guarantee access, so I think that they should be Priority 3.
>
>  - Ian
>
>----------
>References
>----------
>
>[1] http://lists.w3.org/Archives/Public/w3c-wai-ua/2001JanMar/0227.html
>[2] http://server.rehab.uiuc.edu/ua-issues/issues-linear-lc2.html#443
>[3] http://www.w3.org/WAI/UA/WD-UAAG10-20010126/
>
>--
>Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
>Tel:                         +1 831 457-2842
>Cell:                        +1 917 450-8783

Jon Gunderson, Ph.D., ATP
Coordinator of Assistive Communication and Information Technology
Division of Rehabilitation - Education Services
MC-574
College of Applied Life Studies
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
WWW: http://www.w3.org/wai/ua
Received on Wednesday, 21 February 2001 19:49:58 GMT

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