Re: Do we really care about levels?

"Roy T. Fielding" <fielding@avron.ICS.UCI.EDU>
Date: Mon, 26 Sep 94 06:59:57 EDT
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From: "Roy T. Fielding" <fielding@avron.ICS.UCI.EDU>
To: Multiple recipients of list <>
Subject: Re: Do we really care about levels? 
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I don't like the current Level 0 at all -- it makes the text of the
specification difficult to understand and I don't think it accomplishes
its intended purpose.

It does not seem useful to disallow certain types of highlighting --
browsers will just ignore those they don't understand in any case.
Requiring ALT="" in IMG is a nice concept, but it is the kind of thing
I would want in a %HTML.Strict (or some such toggle) rather than as
a separate DTD.

> This is really getting nasty: what level of browser in lynx? It does
> forms and highlighting, but it doesn't do images. This suggests that in
> stead of:
> 	Accept: text/html; level=2
> the more appropriate design is:
> 	Accept: text/html; highlighting=yes; forms=yes; images=no
> This starts to look like more cost than benefits. Hmmm...
> So how do we gracefully deploy changes in HTML?
> Dan

I'll repeat my prior suggestion of <>:

It may be better to go with

    Level 0 -- what all browsers can conveniently render or ignore
    Level 1 -- + images
    Level 2 -- + forms

with the idea being that browsers can signal their preference for
image-free content (i.e. a version of the document that does not depend
on the images for information) and for forms-free processing.

The question of where HTML/3.0 should go is still up in the air, but
I think that can wait until 3.0 is defined.

*Future Note* I propose that ALL extensions to HTML for version 2.1
              be strictly limited to those that fit in Level 0 (as defined
              above).  All other extensions should be postponed to 3.0
              (as Level 3).

.....Roy Fielding   ICS Grad Student, University of California, Irvine  USA