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Re: Content negotiation

From: M. Hedlund <hedlund@best.com>
Date: Wed, 8 Nov 1995 18:38:37 -0700
Message-Id: <v02120d00acc6fea41d1b@[]>
To: Shel Kaphan <sjk@amazon.com>, Brian Behlendorf <brian@organic.com>
Cc: www-talk@w3.org
Shel writes:
>I think we should separate content negotiation from the issue of
>browser capabilities.  Content-negotiation should be more for
>user-preferences, presence or absence of certain helper apps, and
>other coarse grained and dynamic decisions that occur at a fairly high
>level.  Browser capabilities are (a) certain to be too voluminous to
>encode in anything like the Accept header mechanism, and (b) are
>constant properties of given browsers (down to the platform and

Does "browser capabilities" == "HTML tags and attributes recognized"?

If so, can't we just derive this information from DTD's[1]?  DTD's already
exist for Mozilla and Hotjava -- see <URL:http://www.halsoft.com/html/>.

Internet Media Type negotiation ("course grained" in Shel's message above)
is done through Accept.  Language is done through Accept-Language.
Although we may want to make recommendations as to how helper apps should
appear in Accept, basically none of the Accept-* stuff changes.....

.....except, in the Accept header, something of this sort appears:
        Accept: text/html;DTD="-//IETF//DTD HTML 2.0//EN"
        Accept: text/html;DTD="-//Netscape Comm. Corp.//DTD HTML 2.0b2//EN"

("text/html;version=2.0" can be a synonym for the first example above.)

Anyone who cares can get that DTD.  Servers can provide utilities to deal
with the information given in the DTD.  Other servers (or
server-maintainers) might value performance over fine-grained negotiation
and may ignore the DTD.

If a browser author wants to add experimental tags to their browser's
parser, they are strongly encouraged to publish a DTD describing their
experiment.  If they do not, anyone else who wants to, can.


M. Hedlund <hedlund@best.com>

[1] See <URL:http://www.sgmlopen.org/sgml/docs/library/getstart.htm> for
more info.
Received on Wednesday, 8 November 1995 21:37:37 UTC

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