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Re: SC 3.2.5 vs. SC 2.2.4 and G75 and G76

From: Loretta Guarino Reid <lorettaguarino@google.com>
Date: Thu, 24 Jul 2008 19:33:49 -0700
Message-ID: <824e742c0807241933k4e81cd26lce2d232073096df3@mail.gmail.com>
To: sailesh.panchang@deque.com
Cc: public-comments-wcag20@w3.org

On Thu, Jul 10, 2008 at 12:28 PM, Sailesh Panchang
<sailesh.panchang@deque.com> wrote:
> SC 2.2.4 Interruptions: Interruptions can be postponed or suppressed by the
> user, except interruptions involving an  emergency. (Level AAA)
> SC3.2.5 Change on Request:
> Changes of context  are initiated only by user request or a  mechanism  is
> available to turn off such changes. (Level AAA)
> Comment:
> 3.2 deals with making Web page content behave in predictable ways and the
> emphasis is on consistent layout, navigation and identification. This is in
> keeping with the "understanding" principle.
> I believe a change in context caused by  auto updating content (3.2.5)  is
> covered by interruptions (2.2.4) that  upset task focus. Such an
> interruption or change in context makes it difficult to operate (or even
> read) the Web page. So change of context by auto updating content is a
> transgression of the "operate" principle than the "understand" principle.
> Difficulty in understanding posed by auto updating content is a consequence
> of difficulties posed during operation.
> On the other hand, changes in context referred to 3.2.1 or 3.2.2 are also
> unexpected but are based on user action (focus change / form input) and
> certainly hamper understanding. As a consequence it makes operation
> difficult.
> The supporting techniques for 2.2.4 and 3.2.5 too are identical:
> G75 for 2.2.4: Providing a mechanism to postpone any updating of content
> G76 for 3.2.5: Providing a mechanism to request an update of the content
> instead of updating automatically
> I think this is just a play of words and  both SC 3.2.5 and technique G76
> can be deleted without any  loss.

Response from the Working Group
While we agree that listing automatic updates under 3.2.5 (Change on
Request) overlaps somewhat with the requirements of 2.2.4
(Interruptions), the two do not overlap completely in that not all
changes of context would be considered an interruption. For example,
providing a link that causes a movie to be opened in a media player
rather than in the current user agent would not be an interruption,
but would be a change of context.

Regarding G75 and G76, providing a mechanism that postpones or allows
users to configure the frequency of automatic updates (G75) is
different than providing a mechanism that allows users to manually
request them (G76). You are correct however, that G76 should have been
listed under 2.2.4 and we have corrected that error.

Loretta Guarino Reid, WCAG WG Co-Chair
Gregg Vanderheiden, WCAG WG Co-Chair
Michael Cooper, WCAG WG Staff Contact

On behalf of the WCAG Working Group
Received on Friday, 25 July 2008 02:34:31 UTC

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