Re: About tests 37-41 (headers)

At http://www.w3.org/MarkUp/#isohtml it is stated that ISOHTML already 
got a way to forbid skipping header levels in the SGML-DTD of ISOHTML.

I think that avoiding skipping header levels was in the spirit of 
initial's HTML specification authors, but somehow we lost compliance with 
that rule since it was not properly expressed in the new DTDs. (XHTML 2.0 
is repairing this issue, however).

There are some other conditions from the XHTML specification that can not 
be expressed in the DTD (or XML Schema) of XHTML. For example, forms 
should not nest. However it is possible to validate a document with nested 
forms.

Is there an accessibility rule that avoids nesting forms? I guess we all 
agree that such nested forms will not be functional (in general). I think 
that forbidding nested forms has not been considered as an accessibility 
issue (maybe it should be?) because, though not explicitly declared in the 
DTD, it is in the spirit of HTML specification (just as many people think 
that skipping headers is also in that spirit).

Anyway, though not every accessibility condition can be stated in a rule 
within a DTD or XML Schema, as Chris said:

> The tech doc says "Skipping levels in the sequence of headings may create the 
> impression that the structure of the document has not been properly thought 
> through or that specific headings have been chosen for their visual rendering 
> rather than their meaning"
> http://www.w3.org/TR/2006/WD-WCAG20-TECHS-20060427/#H42

So, my questions are:

1.- Is there a way to declare this as "good practice" or "good to have, 
but not required" within WCAG 2.0? WCAG 1.0 already stated that not 
skipping levels was recommended.

<blockquote 
cite="http://www.w3.org/TR/WCAG10-HTML-TECHS/#document-headers"> Since 
some users skim through a document by navigating its headings, it is 
important to use them appropriately to convey document structure. Users 
should order heading elements properly. For example, in HTML, H2 elements 
should follow H1 elements, H3 elements should follow H2 elements, etc. 
Content developers should not "skip" levels (e.g., H1 directly to H3). 
</blockquote>

2.- I still think that a maximum accessibility level (namely AAA), should 
not skip headings because many users may think "that the structure of the 
document has not been properly thought through". Why this is now not 
required/recommended for level 3?

3.- Why will you allow that AAA documents might have undesirable 
conditions like nesting forms or skipping levels? I think it is OK to not 
require strict adherence to A or AA documents, but the maximum AAA level 
documents should have no undesirable conditions like these.

Best regards.

P.S.: I know that accessibility addresses many "grey areas", but the WG 
should find a way to name desirable conditions even though they are not 
required.

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

On Mon, 1 May 2006, Chris Ridpath wrote:

>> I think that it is OK to skip headers for "A level"
>> pages (or maybe also for "AA level"), but a
>> "AAA level" page should avoid bad header hierarchy...
>> 
>
> The latest WCAG techniques document references the issue but does not have a 
> technique or test for it.
>
> So it appears that skipping levels is OK, even for level 3 compliance.
>
> Cheers,
> Chris
>