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RE: alt element (was: naming custom/extended tags)

From: David Wagner <dwagner@kevric.com>
Date: Mon, 14 Feb 2000 11:30:25 -0600
Message-Id: <200002141735.MAA28845@tux.w3.org>
To: <www-html@w3.org>
Firstly, thank you all for helping me grok object and img elements.
Secondly, I have some questions and some comments on naming tags and alt

On naming elements and attributes, where may I find some help on choosing
whether something should be an element or an attribute?  I tried to divine
some pattern from HTML, but from what I have gathered watching these
discussions, there is no particular reason why title is an element and alt
an attribute, when it would seem more appropriate the definitions be
reversed.  So, aside from the obvious that if a tag I need must be able to
contain other elements, and therfore must itself be an element, what are the
guidelines for distinguishing what should be an attribute from an element?

Along a similar line, in a structured document, what is the definition of
content?  I have at times reduced data structures (espcecially when building
an RDF) to a collection of elements and attributes, then wondered which
attribute should really be the text content of each element.  Is content
what the user should see/hear/smell, while structure (elements and
attributes) is all the smoke and mirrors needed behind the scenes?

> -----Original Message-----
> From: www-html-request@w3.org
> [mailto:www-html-request@w3.org]On Behalf
> Of JOrendorff@ixl.com
> 'alt' would provide a way for the author to tell the UA what to use
> and what to ignore when it finds an unsupported tag.  It lets
> the author
> provide useful fallback content, if appropriate (htign wouldn't.)
> If the server has a profile of the client's capabilities, <alt> can be
> processed server-side (whether this is even remotely desirable is
> questionable of course.)

Hopefully alt elements could be nested.  Consider the inclusion of a vector
animation (let's say of DNA-RNA-protein transcription, something easier to
understand when animated) in a format not widely supported, but which looks
great at any resolution and consumes little bandwidth.  There are many
alternatives to this depiction with various advantages and disadvantages:
mp3, quicktime, avi, a sequence of static vector drawings, bitmapped images,
an audio file explaining the animation, HTML/css, and finally a text
description.  It is probably best the UA choose from among these based on
the system's ability to render them and the user's preference.

In addition, a user who does not understand the concept from the animation
may choose to hear the sound or see the steps explained in a sequence of
drawings, in other words may change his or her preferences dynamically.  It
would be very good for browsers to indicate when there are supported
alternatives to an element, and allow users to access them, as some authors
do when they use a capital-D link to indicate HTML describing an image. Of
course, this text should already be in the alt attribute, but if the alt
attribute were adequate, authors wouldn't be linking to an external
description.  (Besides, the alt attribute cannot specify an audible
description of an image, a particularly bad accessibility oversight.)

This doesn't sound all that complicated to standardize and for browsers to
implement.  The sticking point seems to be object/applet paramters.  Well,
IMHO, these should all be specified in the same manner as stylesheets are
used: in a style element containing textural parameters, or with a link to a
seperate parameter file.  Why?  The vast majority of object and applet
paramters control the presentation of the thing: stylistic issues which
should be kept seperate from the document content.  (For animation, remember
time is a dimension, and can be treated the same as positioning on an axis;
just use different units.)

Thanks -David
Received on Monday, 14 February 2000 12:35:26 UTC

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