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Proposed rewording of ISSUE-204 text to address outstanding technical issues

From: Edward O'Connor <eoconnor@apple.com>
Date: Mon, 10 Sep 2012 17:16:19 -0700
To: public-html@w3.org
Message-id: <m21ui9jtws.fsf@eoconnor.apple.com>
Hi all,

Since ISSUE-204 was decided, some technical issues with the adopted spec
text have been raised (in FOs and otherwise). I've attempted to capture
these in Bugzilla.

Currently, the spec says

> User Agents are encouraged to expose the full semantics of hidden
> elements to Assistive Technology when such elements are referenced
> from WAI-ARIA attributes such as aria-describedby.

PFWG representatives have indicated that this clause unduly specifies
changes to WAI-ARIA; I filed

          https://www.w3.org/Bugs/Public/show_bug.cgi?id=18744

to capture this concern.

Additionally, some have interpreted this paragraph to mean that UAs
should include hidden="" elements in the ordinary accessibility tree
when they happen to be referenced with aria-describedby="". I filed

          https://www.w3.org/Bugs/Public/show_bug.cgi?id=18745

to work on text that would avoid this interpretation (which was not the
interpretation intended by the authors of the Change Proposal).

On Friday I got together with James Craig (WAI-ARIA editor) and Maciej
to try to come up with text that would address the above issues. We
posted our new text in Bugzilla:

        https://www.w3.org/Bugs/Public/show_bug.cgi?id=18744#c9

For convenience, here is the proposed text:

> Accessibility APIs are encouraged to allow a way to expose structured
> content while marking it as hidden in the default view. Such content
> should not be perceivable to users in the normal document flow in any
> modality, whether using Assistive Technology or mainstream User
> Agents.
>
> When such features are available, User Agents may thus expose the full
> semantics of hidden="" elements to Assistive Technology when
> appropriate, if such content is referenced indirectly by an ID
> reference or hash-name reference. This allows Assistive Technologies
> to access the content structure upon user request, while keeping the
> content hidden in all presentations of the normal document flow. Some
> examples of where it would be appropriate for the structure of
> hidden="" elements to be exposed to users of AT with such an API
> include:
>
>  * a <map> referenced from <img usemap>
>  * table headers referenced with the headers="" attribute
>
> Cases where it would be inappropriate include
>
>  * <a href> containing a hash name reference to a hidden="" element in
>    the same document
>  * <label for> referencing a hidden="" form element
>
> Other specifications which define elements and attributes which may be
> included in valid HTML documents (such as SVG, MathML, and WAI-ARIA)
> may define how or whether this applies to their elements and
> attributes.

Some things to note:

* The original text was restricted to elements "referenced from WAI-ARIA
  attributes"; the new text applies to elements "referenced indirectly
  by an ID reference or hash-name reference". This addresses PF's
  concern captured in bug 18744.

* Also for bug 18744, aria-describedby="" is no longer used as an
  example. Instead, both positive and negative examples are drawn from
  elsewhere in HTML, and it's left to WAI-ARIA to define how this would
  work with WAI-ARIA attributes.

* Lots of additional text is present which attempts to clarify what is
  meant by "expose the full semantics" to address the issue captured in
  bug 18745.

There's ongoing discussion in Bugzilla (on bug 18744), and I think a bit
more tweaking may be necessary to get as many people on board with the
new text as we can. I'm confident that we'll be able to arrive at text
that everyone can live with, and I hope that those who have FOed to the
ISSUE-204 decision will work with us to address the remaining technical
issues here.

I know we usually don't encourage "+1"-style email on this list, but I'd
love to hear everyone's thoughts on this, even if it's just "yes, this
is an improvement". :)


Thanks,
Ted
Received on Tuesday, 11 September 2012 00:16:46 GMT

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