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RE: Action item: Rewriting 1.3, "Ensure that information, functionality, and structure are separable from presentation"

From: Jason White <jasonw@ariel.its.unimelb.edu.au>
Date: Mon, 25 Apr 2005 19:56:15 +1000
Message-ID: <17004.48831.394672.398114@jdc.local>
To: "John M Slatin" <john_slatin@austin.utexas.edu>
Cc: <Becky_Gibson@notesdev.ibm.com>, <w3c-wai-gl@w3.org>

John M Slatin writes:
 >  
 > <proposed>
 > Ensure that information, structure, and behavior are separable from
 > presentation.
 > </proposed>
 >  
 > Rationale
 >  
 > So the question is whether the word "structure" as defined in the WCAG
 > glossary [1] can carry the weight of "information" in the senses listed
 > above.  I think "structure" is defined in such a way that it probably
 > *can* carry that weight. But I also think that interpreting it that way
 > would be a stretch for the vast majority of our readers (including most
 > of us...). And if I'm right about that we should probably retain the
 > word "information."

I agree with this reasoning.
 >  
 > I'm also concerned about the introductory phrase "Whenever markup or
 > languages permit...": I worry that this would give developers carte
 > blanche to use whatever technologies they want without regard for
 > whether or not those technologies support accessibility (or at least
 > this aspect of it)-- they could simply say that the language/technology
 > they chose didn't "permit" any significant separation of structure,
 > presentation, and behavior, but that's what the client wanted so...
 >  

I share those concerns, but as indicated in an earlier contribution to
this thread I think it is best dealt with in the advice we give
concerning the selection of a baseline. The qualification "to the extent that
the format permits" (or similar) is also problematic.

XHTML permits me to add custom SPAN eleemnts, with class attributes,
to make explicit the grammatical structure of a sentence, as in:
<span class="demonstrative"> This </span>
<span class="verb"> is</span>
<span class="indefinite-article"> a </span>
<span class="common-noun"> sentence. </span>

and one can imagine technologies that process natural language to
increase its accessibility which would benefit from this kind of
treatment; but unless the custom SPAN elements (or similar devices)
are actually standardized somewhere and form part of the technology
baseline of the content, it is superfluous, not to mention tedious and
labour-intensive, for the author to add them. In fact, the better
solution is for the user agents to parse the sentences themselves,
requiring at most only occasional hints from the author.

So, as I suggested earlier, I think guideline 1.3 has to be
relativized to the technology baseline of the content and the risks
John mentions are of a kind that we will just have to live with, in
the expectation that authors will follow our guidance in choosing
baselines.

The success criteria could operate as follows:

1. Stipulate certain types of structure that have to be separable from
presentation for particular classes of content. We already do this.

2. Require that structures specifically provided for in the format of
the content (this format being part of the baseline) be used in a
conventional and supported manner.

By providing for some types of structure explicitly we rule out the
setting of very low baselines; by requiring the use of structures
supported directly by the format we avoid limiting the requirement to
a static list of structures specified in the guidelines.
 > The final phrase-- "to the extent possible for the content"-- raises
 > similar concerns for me.


Actually, it is redundant. In order for 1.3 to apply at all, the
structure has to be in the content, at least implicitly; and if the
format supports making that structure explicit then this is all that
is needed to enable a developer to apply 1.3.
Received on Monday, 25 April 2005 09:56:43 UTC

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