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

From: Charles McCathieNevile <charles@w3.org>
Date: Wed, 21 Feb 2001 20:59:38 -0500 (EST)
To: Jon Gunderson <jongund@uiuc.edu>
cc: Ian Jacobs <ij@w3.org>, <w3c-wai-ua@w3.org>
Message-ID: <Pine.LNX.4.30.0102212057340.24362-100000@tux.w3.org>
No.

It is not about guaranteeing access, it is about providing a way to alleviate
a problem, which (at P1 level) is otherwise guaranteed to prevent access.

I like thje way the proposal is worded, since it makes it clearer just what
must be done in each situtation, but I disagree that it is a priority 3
requirement.

Charles McCN

On Wed, 21 Feb 2001, Jon Gunderson wrote:

  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



-- 
Charles McCathieNevile    http://www.w3.org/People/Charles  phone: +61 409 134 136
W3C Web Accessibility Initiative     http://www.w3.org/WAI    fax: +1 617 258 5999
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Received on Wednesday, 21 February 2001 20:59:39 GMT

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