Re: Proposal For Outline Markup Scheme For HTML 3.0

Keith Rettig (KRettig@ctt.bellcore.com)
Wed, 19 Jul 1995 09:17:25 -0400


Message-Id: <ac31c25008021004765c@[128.96.140.133]>
Date: Wed, 19 Jul 1995 09:17:25 -0400
To: www-html@www10.w3.org
From: KRettig@ctt.bellcore.com (Keith Rettig)
Subject: Re: Proposal For Outline Markup Scheme For HTML 3.0
Cc: simonb@ctt.bellcore.com

Chris Tilbury provided an excellent alternative to our proposal for an
outline markup scheme.  With two minor alterations we fully support his
modified proposal.  It is much simpler to implement and has a lesser impact
on existing browsers than our original proposal.

While reading Chris' proposal, please keep in mind the following.  The
presence of the <LH> tag could obviate the need for IH as proposed by
Chris.

Chris wrote...
[Incidently, does anyone know why we've got <LH> to provide a caption in a
list, and <CAPTION> to provide a caption on everything else?  Yes, I know
<LH> is supposed to put the header at the top of the list, but isn't this
just a presentation issue?]

Our response to that would be to suggest that <LH> be used for the purposes
that we have requested and that  <CAPTION> be used as the current <LH>
does.


The LH's of nested lists can serve in place of IH.  Our other modification
would be to allow the specification of a level to which expansion should
initially occur by providing a value for OUTLINED, e.g. OUTLINED=2 would
expand to the second level.  We feel that relegating outline expansion
levels to a style sheet could result in an uneccessary proliferation of
style sheets.  Also, the presence of an OUTLINED value would serve two
purposes; specification of a level, and the specification of the list into
collapsable form.

The beauty of Chris' approach is that any browsers which do not support
accordian/outline text would simply display the outline as fully expanded.
As would OUTLINED=0.

Finally, we once again propose that the specification indicate that
implementers should provide for automatic outline expansion when an attempt
is made to jump to an "unexpanded" anchor.

So, how about it? Can we add just one attribute to the existing HTML 3.0
markup for lists? Please! :-)

What is our next step for requesting this feature?  Should we re-write our
proposal using this modified design?



Chris' redesign...[snip]
So, how can we achieve this? Well, how about something like this.

<OL OUTLINED>
 <LI>
  <IH>This is the top outline level</IH>
  <P>This is the text below the header. In an Ordered or Unordered
     Outlined list this would not be displayed until the header was
     expanded. The enclosing of this text in the &lt;P&gt; element
     would ensure that the text would hopefully be displayed
     beneath the header on older, legacy browsers</P>
      <UL OUTLINED>
       <LI>
         <IH>This is the next outline level</IH>
         <P>This is the text describing it; again, note that since
            the content.model of the &lt;LI&gt; element is flow and
            flow includes lists, one can include multiple levels of
            outline without extra tags being required.</P>
       </LI>
 </LI>
</OL>

Which could display as

[-]  1.    This is the top outline level

           This is the text below the header. In an Ordered or
Unordered
           list this would not be displayed until the header was
           expanded. The enclosing of this text in the <P> element
           would ensure that the text would hopefully be displayed
           beneath the header on older, legacy browsers.

[+]        *   This is the next outline level

on an "intelligent" browser, as

1.    This is the top outline level

      This is the text below the header. In an Ordered or Unordered
      list this would not be displayed until the header was expanded.
      The enclosing of this text in the <P> element would ensure that
      the text would hopefully be displayed beneath the header on
      older, legacy browsers.

      *    This is the next outline level

           This is the text describing it; again, note that since the
           content.model, of the <LI> element is flow and flow
           includes lists, one can include multiple levels of outline
           without extra tags being required.

on a less intelligent one.

Compared with the proposed scheme, this requires 1 additional
element, <IH>, for Item Header:

   IH (Item Header)

   Permitted Context: Immediately following LI
   Content Model: %text

A single modification to the LI specification[2], which should not
affect the rendering of existing lists in any way whatsoever:

   LI (List Item)

   Permitted Context: UL or OL
   Content Model: Optional Item Header (IH), followed by %flow

And the addition of a single attribute to the OL[3] & UL[4]
specifications

   OUTLINED
     The presence of this attribute indicates to the user agent that
     this is an "outline" list. Outline lists should be rendered as
     an expandable/collapsable list, with the initial view of each
     <LI> being simply the Item Header (IH) if present; otherwise,
     the specific item should be non-expandable. User Agents should
     provide an appropriate mechanism for expanding or contracting
     each LI to display it's full content - in the case of visual
     browsers, this could be by clicking on the numbering or dingbat
     identifying the list item (which can be specified in <LI> using
     the SRC or DINGBBAT attributes).

Personally, this is the absolute limit which I would feel could be
encompassed within the markup without encroaching on completely
presentational issues (which I think all of this is, anyhow).
Anything further, including indicating which levels should be
expanded initially, and which shouldn't, should live in stylesheets.

References:

[1] <URL:http://www.hpl.hp.co.uk/people/dsr/html/CoverPage.html>
[2] <URL:http://www.hpl.hp.co.uk/people/dsr/html/listitem.html>
[3] <URL:http://www.hpl.hp.co.uk/people/dsr/html/seqlists.html>
[4] <URL:http://www.hpl.hp.co.uk/people/dsr/html/bulletlists.html>

Regards,

Chris

--
Chris Tilbury, Estates Office, University of Warwick, UK, CV4 7AL
Tel: +44 1203 523523 x2665                   Fax: +44 1203 524444
MIME mail welcomed      mailto:Chris.Tilbury@estate.warwick.ac.uk

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Keith Rettig (krettig@ctt.bellcore.com)
Simon Blackwell (simonb@ctt.bellcore.com)

Keith Rettig
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