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Re: Comments on PAGEAUTH 2.4: Lists

From: Ian Jacobs <ij@w3.org>
Date: Fri, 19 Mar 1999 12:21:41 -0500
Message-ID: <36F287A5.CFF18C84@w3.org>
To: Charles McCathieNevile <charles@w3.org>
CC: Al Gilman <asgilman@iamdigex.net>, Gerald Oskoboiny <gerald@w3.org>, w3c-wai-gl@w3.org

Here's a proposal:

1) We say something like this:
    Non-visual users often "get lost" in lists, especially those with
    several layers of embedding and those that do not indicate the
    specific level of indentation for each item. Content developers are
    encouraged to use UL for unordered lists and OL for ordered lists
    (i.e., use markup appropriately).  However, until user agents
    a means to identify list context clearly (e.g., by supporting the
    ':before' pseudo-element in CSS2), content developers should
    consider including contextual clues in their lists.

2) We talk about a CSS2 solution:

     The following CSS2 style sheet shows how to provide compound
     for nested lists created with either UL or OL elements.
     Items are numbered as "1", "1.1", "1.1.1", etc.

     <STYLE type="text/css">
        UL, OL { counter-reset: item }
        LI { display: block }
        LI:before { content: counters(item, "."); counter-increment:
item }

3) We talk about a CSS1 solution:

      Until either CSS2 is widely supported by users agents or user
      agents allow users to control rendering of lists through other
      authors should consider providing contextual clues in nested 
      lists. The following CSS1 mechanism shows how to hide the
      end of a list when style sheets are turned on, and to reveal
      it when style sheets are turned off, when user style sheets
      override the hiding mechanism, or when style sheets aren't

        <STYLE type="text/css">
          .endoflist { display: none }
              <LI>Poster paper 
                <span class="endoflist">(End of Paper)</span>
              <LI>Blue writing pens
              <LI>whiteboard pens 
              <span class="endoflist">(End of Pens)</span>
              <LI>paper clips
              <LI>Big lengths of rope. 
              <span class="endoflist">(End of Fasteners)</span>
            </UL> <span class="endoflist">(End of Office

  Note: This example does not help the case of wrapping
        list items. With some more effort, the author
        could put similar markup at the end of each list

  Question: Perhaps it's also helpful to use this mechanism
            at the beginning of each list to say how
            many items are in the list. Any thoughts?

All comments welcome!!

 - Ian  

> We use staiontery of 3 types, each of which is divided into several
> subcatergories:
> 1. Paper - 4 type
>    1. Envelopes
>    2. Notepaper
>    3. Letterhead
>    4. Poster paper
> 2. Pens - 2 types
>    1. Blue writing pens
>    2. whiteboard pens
> 3. fasteners - 3 types
>    1. paper clips
>    2. staples
>    3. Big lengths of rope.
> Provides more clues to navigation and to the implicit structure of the
> list than if unordered lists were used.
> charles
> On Sun, 7 Mar 1999, Al Gilman wrote:
>   At 09:11 AM 3/7/99 -0500, Ian Jacobs wrote:
>   >Gerald Oskoboiny wrote:
>   >
>   >>
>   >> But this doesn't seem like a good example of an ordered list at
>   >> all -- the items in these lists don't have a particular order to
>   >> them (green, purple, and mauve aren't in that order for any
>   >> particular reason.)
>   >>
>   >> I suggest that this example be changed to use list items that
>   >> really ought to be ordered. (like giving instructions on how
>   >> to do something.)
>   >
>   >Yep, I agree.
>   >
>   There is more to this guideline than this exchange reveals.  I was shocked
>   when I first encountered this guideline, because the fact that lists give
>   the appearance of order to things that are semantically sets is one of my
>   hot buttons.  But there is a reason for it.  And it goes beyond just those
>   cases that are natural OL applications.
>   Numbering of list items is a navigation aid for someone using a screen
>   reader, which really treats the document as a sequence of lines.  Braille
>   formatting uses hierarchical numbering of sections and not indenting to
>   show structure for a similar reason.  So the guidelines need to expose this
>   issue.  There is benefit to ordinal marking of lists for navigation for
>   this group.  This is not a pure win-win deal; so the practice has to be
>   applied with a grain of salt.  But there is some motivation to use OL over
>   UL even when the underlying semantics indicate UL.
>   On the other hand, this particular example is so dysfunctional that we had
>   better come up with a better one if we want to pass the laugh test.  A long
>   single-level list would be a better idea.
>   Al
> --Charles McCathieNevile            mailto:charles@w3.org
> phone: +1 617 258 0992   http://www.w3.org/People/Charles
> W3C Web Accessibility Initiative    http://www.w3.org/WAI
> MIT/LCS  -  545 Technology sq., Cambridge MA, 02139,  USA

Ian Jacobs (jacobs@w3.org) 
Tel/Fax: (212) 684-1814 
Received on Friday, 19 March 1999 12:21:15 UTC

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