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Checkpoint 2.3

From: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
Date: Sat, 28 Oct 2000 15:35:38 +1100 (EST)
To: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
Message-ID: <Pine.SOL.4.10.10010281451440.21504-100000@ariel.ucs.unimelb.edu.au>
Checkpoint 2.3, as it stands, asserts that the logical structure of
content must be provided in markup, or in a data model. This requirement,
though fundamentally important to accessibility, is poorly defined, as it
fails to answer the question of which structural characteristics, and
which semantic distinctions, need to be explicitly indicated. In part,
this question can be answered by reference to the Techniques, for it is
here that the detailed consequences, pertinent to each technology, of the
requirement will be elaborated. However, there should also be further
discussion and clarification in the guidelines themselves, for several
reasons. First, the Techniques may not, in themselves be normative
(discussion of this question was postponed by resolution of the working
group). Secondly, if, as has been proposed, guidelines for extending
markup languages, or creating new technologies that are accessible, are to
be written as WCAG 2.0 Techniques (or in parallel with the WCAG 2.0
guidelines), it is desirable to provide more specific explanations of
which structures, and which semantics, are deemed relevant for purposes of
accessibility. Thirdly, existing formats, such as HTML *with the CLASS
attribute, particularly in conjunction with the SPAN and DIV elements)
allow arbitrary flexibility to be exercised in deciding which structural
and semantic distinctions to express in the markup, and at what level of
specificity.

For this reason, I propose:

1. that the discussion of checkpoint 2.3 be amplified with further
explanation and examples; and

2. that the detailed elaboration of the requirement of logical structure,
be reserved to the Techniques.

Here is a rough proposal along these lines, which is by no means complete,
and about which I have some reservations.

<dt>2.3 Use markup or a data model to specify the logical structure of
content.
<dd><p>Note: this allows a diverse variety of presentations, in different
modalities and on different devices, to be generated automatically through
the application of style rules. It also facilitates logical navigation of
the content by the user, a capability which is particularly important in
voice-based interaction or in circumstances where the content is presented
on a low-resolution display or braille device.

<p>The details of which structural aspects of the content should be
expressed in the markup or data model, are set forth in the Techniques
relevant to each technology [link to 2.0 Techniques]. To provide general
guidance however, the following is a non-exhaustive list of structural and
semantic features of content which are considered important:
<ul>
<li>The division of a document into chapters, sections, paragraphs etc;
<li>Lists or groups of related items, for example a bulleted list or a
group of user interface controls;
<li>The division of an image into the distinct objects or items depicted
in it;
<li>Headings, labels, titles etc. These should be associated explicitly
with the information to which they apply, especially in complicated
structures such as tables.
 <li>Emphasized text (e.g. as indicated by font changes in a visual
presentation);
<li>Language changes, especially in multilingual texts where two or more
langauges occur;
<li>The use of specialized notations, such as mathematics or computer
program code;
</ul> </dd>

(end of proposal)
Received on Saturday, 28 October 2000 00:35:47 GMT

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