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Re: Comparison of Smart Headers and HTML5 (ACTION-85)

From: Aaron M Leventhal <aleventh@us.ibm.com>
Date: Fri, 5 Dec 2008 16:12:23 +0100
To: "Ben Millard" <cerbera@projectcerbera.com>
Cc: "Al Gilman" <Alfred.S.Gilman@IEEE.org>, "Michael\(tm\) Smith" <mike@w3.org>, "HTMLWG" <public-html@w3.org>, public-html-request@w3.org, "WAI Liason" <wai-liaison@w3.org>
Message-ID: <OF49B39879.D91BFBFB-ONC1257516.005370A4-C1257516.00538889@us.ibm.com>
Here's a copy of the feedback I sent to the whatwg list. I'm especially 
interested in seeing #2 dealt with because then I can give much better 

1. On this part: 
        "If there is a header cell in the table 
whose corresponding |th 
| element has an ID that is equal to the value of id, then assign the 
first such header cell in tree order to the data cell. " 
I don't want to implement a special local table only 
getElementByIdInTable. I'd rather have this reworded to something like 
"If there is an element in the document with a corresponding ID (via 
getElementById) equal to the value of /id/, and it is a header cell in the 
current table, then assign it to the data cell." 

2. The larger part of algorithm is upside down for our needs. I see a use 
case for providing what headers are associated with a cell, but not the 
other way around. Typically an AT will want to know what labels or headers 
to present to a user when a user navigates to a cell. Therefore, I wish 
the entire algorithm was flipped and tells us what headers are a match for 
a given cell. 

3. The one piece of information we do need when we are on a given <th> is 
whether to expose it with ROLE_ROWHEADER or ROLE_COLUMNHEADER in our 
GetRole() implementation. If scope isn't "row", "rowgroup", "col" or 
"colgroup" then we'll need to base that on the position in the table. It 
seems fairly obvious if the <th> is in an edge (but not corner) position, 
but other cases are less obvious. 

I haven't gone through the algorithm in fine detail yet, mostly because of 
comment #2. We'd have to turn the algorithm inside out in order to 
evaluate it. 

- Aaron

"Ben Millard" <cerbera@projectcerbera.com>
"Al Gilman" <Alfred.S.Gilman@IEEE.org>, "Michael\(tm\) Smith" 
"HTMLWG" <public-html@w3.org>, "WAI Liason" <wai-liaison@w3.org>
12/01/2008 07:47 AM
Comparison of Smart Headers and HTML5 (ACTION-85)

ACTION-85 has a page here:


I have published my comparison of the 2 algorithms:


The advice for HTML5 (incomplete) is at the end:


(The <p> after each <h3> summarises the advice I give for that design 
choice. The subsequent bullet points summarise what led me to that 

Feedback is welcome and encouraged, especially if it's public. I will fix 
mistakes in this document if they are reported publically or privately. 
Including typos. :)

Ian Hickson has told me he plans to review table feedback in mid to late 
December 2008. So I'd like feedback on this document to be sent my way 
before then, if possible. Let's say 15th December 2008, as that's 2 full 
weeks after my deadline to publish this.

Don't forget your Xmas shopping!

Ben Millard
Received on Friday, 5 December 2008 15:13:16 UTC

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