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[#248] Table Proposals

From: Michael Cooper <michaelc@watchfire.com>
Date: Fri, 6 Jun 2003 13:36:40 -0400
Message-ID: <D9ABD8212AFB094C855045AD80FB40DD017E0933@1wfmail.watchfire.com>
To: "WAI GL (E-mail)" <w3c-wai-gl@w3.org>

Here is a new set of table proposals. There are a couple issues that we
couldn't decide on (use of the summary attribute, and use of <thead>,
<tfoot>, <tbody> etc. in layout tables), so those are raised in a separate
message. Hopefully these proposals can be considered clear and appropriate
and accepted wholesale, but if particular ones give us trouble, please send
your thoughts. Michael

1. Data tables and layout tables are two distinct uses of the <table>
element and have different requirements. 

a. Data tables: contain a regular organization of cells, the meaning of
which is contextualized by specific relationships among the cells. Moving a
cell would change the meaning conveyed by the table.

b. Layout tables: organize information visually but do not convey meaning
through the table's structure. Moving a cell may alter the organization of
the information but does not affect intrinsic meaning implied by the
relationship of the cells.

2. Requirements for data tables:

a. Data tables MUST contain <th> header elements to label categories of
data. Headers may be used for columns, rows, or both.
b. Data tables that have more than one row of column headers and/or more
than one column of row headers MUST use additional markup to clarify the
relationship of data cells to their headers. This should include "id" and
"headers" attributes OR "scope" attributes. "scope" attributes MAY require
proper use of <col>, <colgroup>, and <tbody> elements. 
c. Data tables whose structure is not completely apparent by use of the
above header markup SHOULD use the "axis" attribute to provide additional
clarification.
d. Data tables SHOULD use <thead>, <tfoot>, <tbody>, <col>, and <colgroup>
elements to organize rows and columns of information if the logical
structure is more complex than a simple two-dimensional grid.
e. Data tables SHOULD use the <caption> element to label the table.

3. Requirements for layout tables:

a. Layout tables MUST NOT use <th> header elements or any of the header
structure attributes "headers", "scope", or "axis". Document structure
should be conveyed by other structural elements such as headings (<h1> -
<h6>).
b. Layout tables MUST NOT use the <caption> element.
c. The source code order, or default linearization, of layout tables MUST
result in the contents being able to convey the author's intended purpose.

4. Remove the requirement that a text equivalent be provided for layout
tables that render columns of text.

Michael Cooper
Accessibility Project Manager
Watchfire
1 Hines Rd
Kanata, ON  K2K 3C7
Canada
+1 613 599 3888 x4019
http://bobby.watchfire.com/
Received on Friday, 6 June 2003 13:36:38 GMT

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