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Re: Deliverable for Action 72 @headers

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Sun, 24 Aug 2008 15:47:46 -0500
Message-ID: <1c8dbcaa0808241347y127facbbs18fcb03b65d66807@mail.gmail.com>
To: "HTML WG" <public-html@w3.org>
Cc: "Gez Lemon" <gez.lemon@gmail.com>, "James Graham" <jg307@cam.ac.uk>, "Ian Hickson" <ian@hixie.ch>, "W3C WAI-XTECH" <wai-xtech@w3.org>, "Joshue O Connor" <joshue.oconnor@cfit.ie>

For your information from Jim Thatcher June 4, 2007:

> "It may be true that it is possible to
> restructure many complex data tables by adding rowgroup or colgroup
> elements to the table and by altering the spans of cells in such a
> way that the scope attribute can specify the header cells for all
> data cells. I am not convinced but it is true for some of the
> "classic" examples. That process is complicated and cumbersome. It
> basically requires rewriting the table. Compare that with the
> headers/id approach. ANY Table with ANY relationship between heading
> cells and data cells can be defined directly by adding id attributes
> and headers attributes to the cells - not touching the structure of
> the table. ANY table ANY relationship. That is part of the reason why
> you see many examples of simple tables marked up with headers/id when
> they are not necessary and simple scope would work. The simple and
> algorithmic aspects of headers/id is why the screen reader vendors
> all now support it and none support rowgroup and colgroup. The
> algorithm the AT vendors would have to implement for the scope/group
> approach is much more complex to the point that I think it unlikely
> they would ever support it AND it would not catch everything."

User Agent Working Group comments:

> "The 'headers' attribute is
> supported by the major screen readers used in the world (JAWS,
> WindowEyes, ??HAL/SuperNova-still waiting for a reply). WindowEyes
> uses the headers and id attribute combination. WindowEyes does *not*
> use the scope attribute. JAWS has support for headers/id, row and
> column span, and the 'axis' attribute. Assistive technologies,
> browser extensions, and tools that use DOM access also support the
> headers attribute and expose that information through their
> accessibility APIs and to their end users with disabilities and to
> developers. Examples of this include Firefox extensions like FireVox
> and the University of Illinois Firefox accessibility extension, and
> developer tools like Parasoft's WebKing and IBM's RAVEN tool. In
> addition, platform accessibility APIs such as IAccessible2 on
> Windows, ATK/AT-SPI on Linux, and the Java accessibility API all have
> functions for getting the row and column headers. The headers
> attribute, scope attrte, and TH all provided explicit, engineered
> ways for browsers to get row and column headers and expose that
> information to assistive technologies through the accessibility APIs.
> Without these, the browsers and assistive technologies are forced to
> resort to heuristics such as font styling and location (topmost and
> leftmost cells), which is insufficient for complex tables with
> spanned and multiple row/column headers." - Jim Allan.


Best Regards,
Received on Sunday, 24 August 2008 20:48:29 UTC

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