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Re: TBODY

From: Pierre Dubois <duboisp2@gmail.com>
Date: Fri, 25 Jan 2013 11:57:06 -0500
Message-ID: <CAPGwD7jjNnE6_TwFNVbpttar=vunOkFbAhLW=J=odEzKntegQA@mail.gmail.com>
To: WAI Group <w3c-wai-ig@w3.org>
Cc: Userite <richard@userite.com>
Userite wrote Jan 25
>
> If the <tfoot> contains global information then it is in the wrong place. global information should be presented before the data (perhaps in the summary :)

Here some references to support it

http://www.w3.org/html/wg/drafts/html/master/common-idioms.html#footnotes
http://www.w3.org/html/wg/drafts/html/master/tabular-data.html#table-descriptions-techniques



Footnotes vs column summary (tfoot element)

As defined in the HTML5 specification, the tfoot element represents
the block of rows that consist of the column summaries (footers).
(http://www.w3.org/html/wg/drafts/html/master/tabular-data.html#the-tfoot-element)

The question is: What exactly is a "column summary"?

Table footnotes (global information about the tabular data) is
definitely not "columns summary". Column summary is often know as the
"total" row or row group at the bottom the the table. So When you read
that row or row group you get a summary of the data per columns.

When a table have global information defined inside the tfoot, the
elements (tr, th, td) inside the tfoot is used for layout. That create
a hybrid data table combined with a layout table. That make it fail
the WCAG Level A. See F46: Failure of Success Criterion 1.3.1 due to
using th elements, caption elements, or non-empty summary attributes
in layout tables (http://www.w3.org/TR/WCAG-TECHS/F46.html).



Multiple tbody element and WCAG

Having multiple tbody have a role in the accessibility when you use
the technique H63: Using the scope attribute to associate header cells
and data cells in data tables
(http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/H63).

When you have an header cell (th) that is marked with the scope
"rowgroup" it needs to be anchored in a row group (tbody). See the
HTML5 specification:
http://www.w3.org/html/wg/drafts/html/master/tabular-data.html#attr-th-scope-rowgroup



What could be the full potential of using multiple tbody and multiple
colgroup by excluding the printing and the zebra stripping use case?

Here's my answer. What is yours?

When the WCAG technique H63 (scope attribute) or H43 (id/headers
attribute) is use to make a complex HTML table accessible, that can
create two different perception of the same table, one for the screen
readers and one for the visual user. My research to combine both
perception resulted in the elaboration of 12 techniques (WCAG 2.0
style). Also that research resulted to: a proposal to add a new
attribute (hassum) at the table element, a proposal to remove the
scope and headers attribute and a proposal to change the current table
algorithm. (https://github.com/duboisp/Table-Usability-Concept)

Here a few techniques (WCAG 2.0 style), that I drafted, where a visual
user and a screen reader can benefit equally of an HTML table that
have multiple tbody element and multiple colgroup element. (All the
technique and related documentation -
http://wet-boew.github.com/wet-boew/demos/tableparser/index-eng.html)
* Defining a Data Row Group -
http://wet-boew.github.com/wet-boew/demos/tableparser/rowgrouping-techniques.html
* Summaries a Data Row Group -
http://wet-boew.github.com/wet-boew/demos/tableparser/summariesrowgroup-techniques.html
* Summaries a Data Column Group -
http://wet-boew.github.com/wet-boew/demos/tableparser/colgroupsummary-techniques.html




Cheers

Pierre
Received on Friday, 25 January 2013 16:57:40 GMT

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