RE: [html-techs] Table Type

Maybe Yvette has hit upon another test for distinguishing layout tables
from data tables:

If the same effect could be achieved using CSS, it's a layout table.

?

John


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-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
Behalf Of Yvette P. Hoitink
Sent: Tuesday, February 10, 2004 9:46 am
To: 'Chris Ridpath'; 'WAI WCAG List'
Subject: RE: [html-techs] Table Type



Chris:

> 
> How to determine if a table is data or layout:
> 
> Discussed at length on this mailing list[2][3][4] etc.
> In summary - If cells can be moved without affecting their
> intrinsic meaning then it's a layout table. Corollary - If 
> moving a cell affects its intrinsic meaning then it's a data table.
> 

Sorry to open this cesspit again, but I really think tables used for
LAYOUT
are layout tables, even if moving a cell can affect its intrinsic
meaning.
There will always be grey areas: tables used for layout that might
benefit
from semantic markup. But does that make them data tables?

Hypothetical example: If I have have a 2x2 (layout) table to divide my
text
in two rows with headers to the left in separate cells, exchanging those
cells can affect their intrinsic meaning as well because those texts are
now
associated with different headings. Does that make it a data table? I
don't
think so. The table has no benefit here besides the visual aspect, the
same
effect could be achieved through CSS. I see no value in using the
semantic
markup for data tables here so to me this is definitely a layout table
even
if it fits your definition. 

A more interesting example is if you use a table to do the layout of a
form
(labels in column 1, inputs in column 2) Moving a cell changes its
intrinsic
meaning so it fits your definition of a data table, a viewpoint shared
by
Jim Thatcher [1].

I still think of this as a layout table though, but I can see the value
in
associating headers with the cells. From a practical point of view it
may be
very helpful to use the semantic markup for data tables in tables used
to
layout forms, but on a principal level I do not regard tables used for
form
layout as data tables. 

An example of a search form which would benefit from more semantic
markup
for the table can be found in a Dutch genealogical website:
http://www.genlias.nl. I can't give you a direct link to the search
page, so
please select English (top right corner) -> Searching the Genlias
database
(text above the looking glass). 

This search form consists of three columns: column one has the labels,
column two has the inputs for the first person you're looking for and
column
three has the inputs for the second person you're looking for. The
meaning
of an input is derived from two axis: the label and the person.
Associating
the labels correctly with their inputs in HTML is not possible in this
case,
since HTML only allows one input per label. The authors have used <th>
to
indicate the column headers, but no other semantic markup.  

Yvette Hoitink
CEO Heritas, Enschede, The Netherlands
E-mail: y.p.hoitink@heritas.nl

[1] Jim Thatcher argues tables to layout forms are data tables:
http://lists.w3.org/Archives/Public/w3c-wai-gl/2000JanMar/0406.html

Received on Tuesday, 10 February 2004 11:14:36 UTC