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Re: Microsoft IE -- it just gets better and better

From: Larry Masinter <masinter@parc.xerox.com>
Date: Sat, 27 Jan 1996 12:10:13 PST
To: www-talk@w3.org
Message-Id: <96Jan27.121019pst.2733@golden.parc.xerox.com>
As far as I can tell, the HTTP working group and its
content-negotiation subgroup doesn't have a solution to the problem of
how to do the full complement of feature-set negotiation that is
currently supported by user agent.

We have a lot of ideas of how it *might* work, and are aware of a lot
of issues that must be considered, etc. But not as yet a workable
proposal that satisfies all the constraints, or a generally agreed
prioritization of the constraints.

The general paradigm is:
  Client says what it can do
  Server can serve varying content based on what client can do
  Server's response says whether it varied and how

The rules are:

- Most servers don't care, most content isn't variable. Put the
  protocol burden on those that care, not those that don't.  All
  negotiation must be optional

- The 'feature set' doesn't correspond necessarily to either things
  that are expressible in DTDs or as media types. Some clients want to
  vary based on known bugs in various browsers.

- Sometimes content wants to vary based on user settings (does user
  override server 'background' and 'color' advice), on client
  capabilities (black and white monitor, small PDA screen, etc.)

Under these rules, what is a mechanism for registering features and
feature sets that content providers care about?

Right now, we're considering how to allow content negotiation not only
on media type (text/html vs. text/netscape-html) but also media type
parameters (text/html;level=1;charset=iso-2022-jp vs
text/html;level=2;charset=iso-8859-5) and media type characteristics
that are not parameters (application/postscript color vs
application/postscript greyscale or image/gif version=gif89a vs
image/gif version=gif87a). We haven't figured out yet how to specify
even  this level of content type negotiation, and dealing with the
additional subtleties doesn't seem to be within reach.

Repeating "this is a problem that needs to be fixed" doesn't help
much. The idea of having user-agent registration of feature sets and
making the feature set content be globally available (e.g., content
providers could contact the browser provider's web site to retrieve
the set of features that a particular version supported) might work,
but the details of feature registration are fuzzy.

Could most of this be handled with media type registration? E.g., if
Netscape were to accept: text/html and text/netscape-2.0-html, then
Microsoft's browser could express its willingness to accept either or
both. Is this a workable solution?
Received on Saturday, 27 January 1996 15:10:41 GMT

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