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A generalized <summary> element

From: Leif Halvard Silli <lhs@malform.no>
Date: Fri, 05 Jun 2009 13:52:30 +0200
Message-ID: <4A2906FE.3090709@malform.no>
To: Janina Sajka <janina@rednote.net>
CC: Ian Hickson <ian@hixie.ch>, Sam Ruby <rubys@intertwingly.net>, Chris Wilson <Chris.Wilson@microsoft.com>, Michael Cooper <cooper@w3.org>, Dan Connolly <connolly@w3.org>, Mike Smith <mike@w3.org>, W3C WAI Protocols & Formats <w3c-wai-pf@w3.org>, Gez Lemon <gez.lemon@gmail.com>, Laura Carlson <laura.lee.carlson@gmail.com>, "wai-liaison@w3.org" <wai-liaison@w3.org>, John Foliot <jfoliot@stanford.edu>, www-archive <www-archive@w3.org>, public-html@w3.org
Janina and everyone.

(Personal response.)

In our internal debates at the HTML4all.org initiative, ideas 
about a generalized <summary> element was put forward. By 
generalized, it was meant that it could play the summarizing role 
both for <table>, <figure> and (perhaps) for <canvas>.

The very idea about a <summary> element *only* for <table> has 
already been presented for Ian, but the idea was put aside due to 
serious DOM compatibility problems with current Web browsers. As a 
response, I proposed to have the <summary> element /inside/ 
caption, however Ian responded that it was not clear to him that 
it was necessary to distinguish the summary from the caption in 
that way. Also, my HTML4all colleges did not support making the 
summary feature dependent on presence of <caption> in any way.

However, <summary> as child of <figure> (and <canvas>) should not 
have the same serious DOM issues that <summary> as child of 
<figure> has. <figure> even allows to move the table caption to 
the caption of the <figure> element:

"When a table element is in a figure  element alone but for the 
figure's legend, the caption element should be omitted in favour 
of the legend."[1] (In Ian's proposal, one would then move the 
summary content into the legend, together with caption content.)

And as long as a table doesn't have a <caption> element, then the 
DOM problems of the <summary> element almost disappears. Hence, in 
those cases when one move the content of <caption> to the 
<figure>'s <legend> element, the use of <summary> as child of 
<table> would not face the same level of DOM problems.

Thus, if the working group decides that, in line with the WCAG 2.0 
requirement, the summary feature needs to be a 
"programmatically-determined mechanism"[2][3], the <figure> gives 
us two options w.r.t. a <summary> element: <summary> could be a 
child of <table> or a child of <figure>.

In a summary: If we are not looking narrowly at the <table> 
summary problem, but expand the problem to <figure> and <canvas>, 
then it should be easier to introduce the <summary> element.

[1] 
http://www.whatwg.org/specs/web-apps/current-work/multipage/tabular-data.html#the-caption-element
[2] http://esw.w3.org/topic/HTML/SummaryForTABLE
[3] 
http://www.w3.org/TR/UNDERSTANDING-WCAG20/conformance.html#uc-programmatically-determined-head 

-- 
leif halvard silli
Received on Friday, 5 June 2009 11:53:13 GMT

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