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Re: [wcag2] "complete start and end tags"

From: Christophe Strobbe <christophe.strobbe@esat.kuleuven.be>
Date: Wed, 04 Mar 2009 15:50:49 +0100
Message-Id: <>
To: Jens Meiert <jens@meiert.com>
Cc: w3c-wai-gl@w3.org
Hi Jens,

At 20:02 2/03/2009, Jens Meiert wrote:
>The parsing section states [1]:
> > In content implemented using markup languages, elements have
> > complete start and end tags
>HTML specifies tags that are optional (see e.g. tags that are optional
>in HTML 4 [2]). Does guideline 4.1.1 (the guideline and all related
>documents seem to be unclear about this) thus disallow what is allowed
>in HTML? If yes, why (exactly)? If it does not, is there a chance that
>a clarifying note is added, probably to the Errata?

The end of SC 4.1.1 says: "...except where the specifications allow 
these features."
So for each HTML 4 element where the specification allows the 
omission of end tags, WCAG 2.0 allows the same.
This was recently discussed on the WCAG mailing list [3] and will be 
addressed in the documentation by adding the following failure example to


Failure Example 7: img and input elements that are not self-closing in XHTML

The following XHTML code fails because empty elements must have an 
end tag or a start tag that ends with />.

<img src="spacer.gif" alt="">

<input type="text" ...>

Note: HTML 4 does not require that empty elements have have an end 
tag, so the examples above would not fail in HTML.

Related links:
* XHTML 1.0, 2nd edition: 4.6: Empty Elements: 
* HTML 4.01: 3.2.1: Elements: 


Does this sufficiently address your concern?

>[1] http://www.w3.org/TR/WCAG20/#ensure-compat
>[2] http://meiert.com/en/blog/20080601/optional-tags-in-html-4/

[3] See the thread starting at 

Best regards,

Christophe Strobbe

>Jens Meiert

Christophe Strobbe
K.U.Leuven - Dept. of Electrical Engineering - SCD
Research Group on Document Architectures
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Received on Wednesday, 4 March 2009 14:51:45 UTC

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