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Re: Review of navigation bar issues for thursdays conference call

From: Charles McCathieNevile <charles@w3.org>
Date: Tue, 24 Aug 1999 22:47:13 -0400 (EDT)
To: Al Gilman <asgilman@iamdigex.net>
cc: w3c-wai-ua@w3.org, w3c-wai-gl@w3.org
Message-ID: <Pine.LNX.4.10.9908242233090.12722-100000@tux.w3.org>
As a refinement to general strategies for naviagtion I like it, although I am
loath to recomend it as something that should be done instead of correcet use
of markup, since the effective message is that it is pointless bothering with
structured markup since effective strategies don't use it.

Thinking some more:

Title is human readable metadata about almost any element. As such it should
be renderable (at the discretion of the user.

So we can either use it to bypass the role of strongly typed data, such as
HTML marked up accroding to the intended meanings of the elements as laid out
in the specification, by using the title as a means of directly communicating
verbally the same semantics which we use visually. This seems to me an
equivalent to reverting to HTML 3.2 presentational markup, on the basis that
we can now provide a non-visual equivalent. For HTML this seems a bad
strategy. (The rules change a bit in XML were you can declare your own
structure, and you declare separately how the various elements ought to be
rendered. This allows you to declare something based on your own
understanding of visual semantics, and structure it according to the logic
behind those semantics. The structure is made explicit in the structuring of
the XML DTD/schema/profile. I suspect that in writing presentation based,
poorly structured HTML, people are selecting the particular elements they
want from a given set. So starting from an empty set, and creating types of
things could induce people to provide more structured semantics in a more
natural way.)

So I am still a fan of map, which is an HTML element created for the purpose
of holding a collection of links.

Charles McCN

On Tue, 24 Aug 1999, Al Gilman wrote:

  At 04:43 PM 8/24/99 -0700, Jon Gunderson wrote:
  >Option 1:
  >Using the DIV element and some type of CLASS or NAME identifier:
  >PROs: Easy to implement and author
  >CONs: There is no mechanism to reserve class names in HTML, there could be
  >conflicts if specific class names are used
  Variation: the TITLE and DIV approach.
  After today's coordination group call, Len came up with the idea that
  perhaps the TITLE attribute is a key resource.  If authors do the right
  thing with the TITLE, maybe we don't need the UA to recognize some
  particular CLASS to do the right thing.  Let's see what we can do if we
  pursue that idea.
  The basic dodge is that for things you want to move high up in the
  navigation structure, you don't TITLE too many of their ancestors in the
  parse tree; and for things you want to hide or minimize you add DIV
  structures with TITLEs so that the collection gets listed rather than the
  members (unless the user explicitly enters the collection).
  The User Agent method that goes with this markup strategy is hierarchical
  navigation of an Effective Table of Contents tree.  The Effective Table of
  Contents tree is the parse tree except that containers that have no TITLE
  attribute on them are ignored or equivalently flattened.  Elements below
  them act (in the effective tree) as though they were directly descended
  from the next TITLE-bearing ancestor up the tree.
  The trick here is that DIV, on the other hand, lets us push things _down_
  the tree.  We can encapsulate and quickly skip the page masthead, while the
  TITLE technique lets us ignore non-semantic superstructure like layout tables.
  The attached three files are 1) the original web page from Amazon.com 2)
  the modified page with TITLE and DIV added according to this technique and
  3) the top level of the resulting effective table of contents.
  Think about it.

--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
Received on Tuesday, 24 August 1999 22:47:14 UTC

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