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Re: WCAG 2.0 4.1.1 Parsing (elements have complete start and end tags)

From: Christophe Strobbe <strobbe@hdm-stuttgart.de>
Date: Mon, 10 Feb 2014 11:37:05 +0100
Message-ID: <52F8ABD1.6040000@hdm-stuttgart.de>
CC: "w3c-wai-gl@w3.org" <w3c-wai-gl@w3.org>, HTMLWG WG <public-html@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Hi,

On 9/02/2014 16:10, James Nurthen wrote:
> Steve, 
> The complete text is
> "4.1.1 Parsing: In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features. "
>
> As you have stated, the html specification allows certain end tags to be optional and some have no end tags so there is no issue with 4.1.1 as the specification allows these features.

Success Criterion 4.1.1 wanted to require certain markup characteristics
that correspond well with XML's concept of well-formedness but without
relying on that concept. This was before HTML5 became significant, and
the criterion also had to work for HTML 4.01 without using obscure SGML
concepts (and I don't mean the DTD).
By the way, HTML 4.01 did not only make certain end tags optional but
also certain start tags, i.e. on the elements HTML, HEAD, BODY and
TBODY.  And even in HTML 4.01, element such as IMG, INPUT, OPTION, COL,
META, BR, AREA, LINK and HR were allowed to have an end tag; the SGML
DTD here merely prohibited the presence of content between the start and
end tag. (See
<http://www.w3.org/TR/1999/REC-html401-19991224/sgml/loosedtd.html>.
HTML 5 also allows the omission of start tags on certain elements:
<http://www.w3.org/TR/html5/syntax.html#syntax-tag-omission>.)

Best regards,

Christophe

>
> Regards,
> James
>
>
> On Feb 9, 2014, at 5:58 AM, Steve Faulkner <faulkner.steve@gmail.com> wrote:
>
>> criteria 4.1.1 [1] parsing, requires complete start and end tags for all elements.
>>
>> "In content implemented using markup languages, elements have complete start and end tags"
>>
>> in HTML end tags certain end tags are optional [2] and certain elements have no end tags (<img>, <input> etc.) How do we explain/reconcile this disparity?
>>
>>
>>
>> [1] http://www.w3.org/TR/WCAG20/#ensure-compat
>>
>> [2] http://www.w3.org/html/wg/drafts/html/master/syntax.html#syntax-tag-omission:
>> --
>>
>> Regards
>>
>> SteveF
>> HTML 5.1
>>
-- 
Christophe Strobbe
Akademischer Mitarbeiter
Adaptive User Interfaces Research Group
Hochschule der Medien
Nobelstraße 10
70569 Stuttgart
Tel. +49 711 8923 2749
Received on Monday, 10 February 2014 10:37:41 UTC

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