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RE: About tests 37-41 (headers)

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Sun, 19 Feb 2006 20:17:36 -0600
To: "'Vicente Luque Centeno'" <vlc@it.uc3m.es>, "'Chris Ridpath'" <chris.ridpath@utoronto.ca>
Cc: <w3c-wai-gl@w3.org>
Message-ID: <013f01c635c3$d2d299f0$096fa8c0@NC6000BAK>

Good work on codifying this.

There was a question though about whether this strict an application of the
headers was required by the success criterion or even by the HTML spec.  

Does someone remember where we came down on this at the meeting? 

Gregg

 -- ------------------------------ 
Gregg C Vanderheiden Ph.D. 
Professor - Ind. Engr. & BioMed Engr.
Director - Trace R & D Center 
University of Wisconsin-Madison 
The Player for my DSS sound file is at http://tinyurl.com/dho6b 

-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf
Of Vicente Luque Centeno
Sent: Sunday, February 19, 2006 6:23 PM
To: Chris Ridpath
Cc: w3c-wai-gl@w3.org
Subject: About tests 37-41 (headers)


Hi,

I have improved the formalization rules for headers. The following XPath
expressions address all headers that skip a downward sequence, according to
tests 37-41.

For all of them (except for h1):

* The preceding header is calculated. If none, current header is badly
placed.

* We take the closest preceding header to the current one (we get that with
the [1]).

* We check if that closest header is OK:
H6's closest preceding header must be a h5 or h6.
H5's closest preceding header must be a h4 or h5 or h6.
H4's closest preceding header must be a h3 or h4 or h5 or h6.
H3's closest preceding header must be a h2 or h3 or h4 or h5 or h6.
H2's closest preceding header must be a any header.
For all: otherwise, current header is badly placed.

Comments?

The rules are the following:

//h6[not(preceding::*[self::h1 or self::h2 or self::h3 or self::h4 or
self::h5 or self::h6][1][self::h5 or self::h6])]

//h5[not(preceding::*[self::h1 or self::h2 or self::h3 or self::h4 or
self::h5 or self::h6][1][self::h4 or self::h5 or self::h6])]

//h4[not(preceding::*[self::h1 or self::h2 or self::h3 or self::h4 or
self::h5 or self::h6][1][self::h3 or self::h4 or self::h5 or self::h6])]

//h3[not(preceding::*[self::h1 or self::h2 or self::h3 or self::h4 or
self::h5 or self::h6][1][self::h2 or self::h3 or self::h4 or self::h5 or
self::h6])]

//h2[not(preceding::*[self::h1 or self::h2 or self::h3 or self::h4 or
self::h5 or self::h6][1])]

//h1[not(true())] (which is //h1[false()], which is () )

Vicente Luque Centeno
Dep. Ingeniería Telemática
Universidad Carlos III de Madrid
http://www.it.uc3m.es/vlc

On Thu, 16 Jun 2005, Vicente Luque Centeno wrote:

>
> All these examples also work with my rules :-)
>
> On Wed, 15 Jun 2005, Chris Ridpath wrote:
>
>> These tests are designed to detect when header levels are skipped in 
>> a downward sequence. For example:
>> h1 followed by an h2 is OK
>> h1 followed by an h3 is bad
>> 
>> Another example:
>> h3 followed by an h4 is OK
>> h3 followed by an h5 is bad
>> 
>> Header levels can be skipped in an upward sequence. For example:
>> h4 followed by an h2 is OK
>> 
>
>> On Wed, 15 Jun 2005, Vicente Luque Centeno wrote:
>>> Those h2 having no preceding h1 are an error:
>>> 
>> The group does not have a test for whether the first header in the 
>> document must be an h1.
>
> Neither of my expressions say that explicitly. However, by proper 
> deduction and combination of my rules, you will implicitly obtain that 
> there is no other possibility. So, yes, the first header in the 
> document must be an h1 (or there should be no header at all) if tests 
> 37-41 should be followed. There is no explicit rule for that, but it 
> is derived from tests 37-41.
>
>> There are no tests that check for multiple h1s in the same document.
>
> That's why I did not include a rule saying:
>
> count(//h1) <= 1
>
> Cheers.
>
> Vicente Luque Centeno
> Dep. Ingeniería Telemática
> Universidad Carlos III de Madrid
> http://www.it.uc3m.es/vlc
>
>
Received on Monday, 20 February 2006 02:17:53 GMT

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