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Check TABLE elements for valid "summary" attribute (Technique 5.5.1 )

From: Wendy A Chisholm <wendy@w3.org>
Date: Fri, 18 Feb 2000 17:49:27 -0500
Message-Id: <4.2.0.58.20000218173933.00a8a300@localhost>
To: w3c-wai-er-ig@w3.org
In Len's comments from the 23rd of January [1] about the 21 December draft 
[2] he asked:
<blockquote>
"Technique 5.5.A Check table for valid SUMMARY"
I don't understand this guideline. Isn't a caption enough and Table headers 
enough, at least if it's a simple table? A summary would merely recite 
what's in the caption and headers anyway. This is a WCAG issue.
</blockquote>

The WCAG group discussed this.  Their conclusion was incorporated into the 
11 February HTML Techniques for WCAG document 
[http://www.w3.org/WAI/GL/WCAG10-HTML-TECHS/#tables].

I have captured their conclusion in the following proposal:
<blockquote>
Technique 5.5.1 [priority 3] Check table for valid "summary" attribute
Discussion Status:discussion complete
Evaluation:TABLE elements should have a valid "summary" attribute for table 
where it is difficult to determine the relationship among cells. A summary 
is especially important for tables with nested headings, cells that span 
multiple columns or rows, or other relationships that may not be obvious 
from analyzing the structure of the table but that may be apparent in a 
visual rendering of the table.
If a CAPTION element is not provided, providing a summary might be even 
more critical, depending on how hard the table it to decipher.
Valid SUMMARY attributes:
Not allowed - NULL SUMMARY value ("")
Not allowed - SUMMARY value of spaces (" ")
Suspicious - SUMMARY value of placeholder SUMMARY values

Example of a message to be displayed:
For missing summary - "Table is missing a summary."
Suggested prompt to user -
"In the summary, describe the purpose of the table (either layout or data). 
For example  ''This table charts the number of cups of coffee consumed by 
each senator, the type of coffee (decaf or regular), and whether taken with 
sugar.
Additional help text: A summary of the relationships among cells is 
especially important for tables with nested headings, cells that span 
multiple columns or rows, or other relationships that may not be obvious 
from analyzing the structure of the table but that may be apparent in a 
visual rendering of the table. A summary may also describe how the table 
fits into the context of the current document. If no caption is provided, 
it is even more critical to provide a summary.

Repair Technique:
Allow the user to enter a summary of the table.

Test Files and Discussion Files:
Link to test file for this technique.
</blockquote>

[1] http://lists.w3.org/Archives/Public/w3c-wai-er-ig/2000Jan/0059.html
[2] http://www.w3.org/WAI/ER/IG/ert/ert-19991221.html

--
wendy a chisholm
world wide web consortium
web accessibility initiative
madison, wi usa
tel: +1 608 663 6346
/--
Received on Friday, 18 February 2000 17:45:27 GMT

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