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WAI class use, attribute quoting, and name capitalization

From: Harvey Bingham <hbingham@acm.org>
Date: Mon, 02 Apr 2001 00:20:52 -0400
Message-Id: <>
To: w3c-wai-er-ig@w3.org
Cc: wai-xtech@w3.org

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.


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
>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.


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

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
Invited Expert, W3C Web Accessibility Initiative
Received on Monday, 2 April 2001 01:08:25 UTC

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