Re: Layout versus data tables proposal for null summary attribute

In the case of images I accept that  an alt="" can be a placeholder for a description to be determined and is incorrect use of alt on a Web page that is finished and  has parked whatever QA tests(if any) it is put through by the author. Summary="" for layout tables is quite like Alt="" for decorative images  that do not need an description. This is a practical way of letting accessibility evaluation  tools know that a table is indeed a layout table. A data table does not   need a summary="" if one chooses not to define a summary. A non-null summary can be used when needed. I support this approach in the interest of auto detection of layout and data tables although I agree with Jesper Tverskov's   statement: "
Best practice should always be to use an attribute when needed, and to leave it out when not needed."
In complex data tables  with nested headers that need headers-id association one might not find th at all. Some authors  feel that if headers-id are indeed providing  the  linkage for data and header cells, they do not want  to use th which also changes appearance to center and bold for the header cell content. Styling can be used to control this effect but again it is deemed unnecessary coding by some authors. Such tables typically  would be expected to have a summary explaining the table's structure to facilitate navigation by screen reader users.  Not having th  does not affect screen reader users when headers-id association is done correctly in such tables .
Sailesh Panchang
Senior Accessibility Engineer 
Deque Systems,11180  Sunrise Valley Drive, 
4th Floor, Reston VA 20191
Tel: 703-225-0380 Extension 105 
E-mail: sailesh.panchang@deque.com
Fax: 703-225-0387
* Look up <http://www.deque.com> *

Jesper Tverskov wrote:
I will strongly argue against the idea of using summary="" for layout
tables. It is a clumsy approach to make nice and correct markup just
like using alt="" for images just being decoration.
Test if headings exist. If not it is a layout table.