- From: Harvey Bingham <hbingham@acm.org>
- Date: Mon, 02 Apr 2001 00:20:52 -0400
- To: w3c-wai-er-ig@w3.org
- Cc: wai-xtech@w3.org
Summary:
In August 2000 I explored the use of the class="..." attribute within
WAI guideline, technique, and checkpoint list documents of WCAG, AT,
UA, and ER at that time.
A small set of values for class="value" are included in the default.css
used for WAI documents.
The documents studied include many more values.
A new class="value" presumably is added by an author to make a useful
distinction for the user. Such addition may require an augmented
stylesheet to describe what to do with it. Any attempt by a user of
assistive technology will need to know how to recognize the author's
reason for such class values, and distinguish among those that are
significant. That is asking a lot from the assistive technology.
Few class values are explicitly included in the html head of the WAI
documents. I believe there are many more class values identified than
are included in the default WAI css stylesheet.
I also noted some attribute values were unquoted, and some name case
variations appear. These are inappropriate for moving forward to either
XHTML or any XML application.
Motivation:
At 2000-08-18 15:58-0400, Leonard R. Kasday wrote:
>I had an action item from the last telecon on writing up a straw proposal
>on <em>making classes accessible</em>. They are posted at
>
>http://www.w3.org/WAI/ER/IG/classuse.html
>
>Two questions:
>
>1. Would this be of practical value?
>2. Is is philosophically acceptable?
Len's points include the confounding of class values for presentation
guidance on a set of elements, with alternative use by user agents.
He notes that title is an alternative for description. He describes
association of title value with class value.
Results:
The list of class attribute values is larger than the 14 values
that Len Kasday had indicated. The semantics for several are not suggested
by their names. I wonder if CSS support for these documents covers all of
them? Many are missing in the default.css provided with WCAG at that time.
[# Today (2001-04-01 I checked for any local class definitions in
<style>...</style> in the html document heads. The few found are
noted below.]
For each of the documents of the working groups, I show the total count
of class="value" followed by the counts for each of the distinct values.
I use a two-letter code for each document in each set. That allows some
intra-document comparisons.
1. Summary of class attribute values in WCAG htm files
Count Code Filename
93 cl cl990505.htm WCAG Checklist
537 te te990505.htm WCAG Checklist table form
363 wc wc990505.htm WCAG 1.0
Count Codes Class
12 te ainst
# 16 cl checkhead
# 65 cl checkinfo
301 te wc checkpoint
3 wc CHECKPOINT
28 te wc checkpoints
1 wc conform
3 cl te wc copyright
9 te css-example
9 te deprecated-example
40 wc dfn-instance
1 te dropcap
42 te einst
50 te example
16 wc GLOSSARY
53 wc glossary
14 wc guideline
3 cl te wc head
1 te nav
12 cl te wc navbar
1 te navigation-bar
1 te newbullet
15 te wc nonb
17 te wc noprint
9 cl te wc notoc
103 te wc noxref
57 te off
5 te quicktest
2 te section2
14 wc subhead
# 3 cl table
12 te wc toc
24 te wc tocline2
51 te wc tocline3
993 Total class occurrences, 34 different class values.
# Local style for use in table row and in div (unlisted above)
to center table.
2. Summary of class attribute values in htm files for ATAG
Count Code Filename
182 at atag10.htm Authoring Tool Accessibility Guidelines 1.0
40 cl clatag10.htm ATAG Checklist
76 ct ctatag10.htm ATAG Checklist Table
419 tc tcatag10.htm ATAG Techniques
Count Codes Class
# 4 ct checkhead
# 28 ct checkinfo
144 at tc checkpoint
14 at tc checkpoints
2 at tc conform
4 at cl ct tc copyright
82 at tc dfn-instance
2 at tc glossary
14 at tc guideline
4 at cl ct tc head
16 at cl ct tc navbar
11 at tc nonb
32 at tc noprint
28 at cl ct tc notoc
51 at cl ct tc noxref
1 at priorities-specific
49 at cl ct tc priority1
53 at cl ct tc priority2
31 at cl ct tc priority3
22 at cl ct tc priorityR
# 4 ct table
74 tc techniques
1 tc technologies
9 at tc toc
15 at tc tocline2
22 at tc tocline3
717 Total class occurrences, 26 different class values.
# Local style for use in table row and in div (unlisted above)
to center table.
3. Summary of class attribute values in htm files for User Agent Guidelines
Count Code Filename
13 cl clua.htm User Agent checklist
114 ct ctua.htm User Agent checklist table
689 ua ua10610.htm User Agent Guidelines 2000-06-10
Count Codes Class
# 14 ct checkhead
# 84 ct checkinfo
118 ua checkpoint
19 ua checkpoints
3 cl ct ua copyright
195 ua dfn-instance
86 ua glossary
4 ua GLOSSARY
11 ua guideline
11 ua guideline-box
3 cl ct ua head
12 cl ct ua navbar
2 ua nonb
87 ua noprint
9 cl ct ua notoc
52 cl ct ua noxref
33 cl ct ua priority1
24 cl ct ua priority2
12 cl ct ua priority3
11 ua subhead
3 ct table
4 ua toc
4 ua tocline2
11 ua tocline3
4 ua tocxref
816 Total class occurrences, 25 different class values.
# have local <style tr:checkhead ...> and <style tr:checkinfo ...>
4. Summary of class attribute values in htm file for ERT working draft
Count Code Filename
75 er ert00823.htm ERT 2000-08-23 working draft
Count Codes Class
1 er copyright
7 er E
1 er head
4 er navbar
2 er notoc
2 er toc
29 er tocline2
29 er tocxref
75 Total class occurrences, 8 different class values.
5. Element and Attribute Name Capitalization
I also note inconsistent use of capitalization. Upper-case element names are
used in the WCAG checklist and the table version of it. A mixture, some
capitalized, some not, are used in WCAG.
In ERT, most, but not all tags are uppercase, with inconsistency in
individual tags (for example <a ...> and <A ...>.)
I suggest that as we move toward XHTML or XML, we should use lower-case
element type names and attribute names. We certainly should avoid a
mixture.
6. Attribute Name Quoting
XML and XHTML require that all attribute values must be quoted, either by
matching "..." or '...'. That has not been consistently used in the WAI
html documents.
Regards/Harvey Bingham
hbingham@acm.org
Invited Expert, W3C Web Accessibility Initiative
Received on Monday, 2 April 2001 01:08:26 UTC