Re: ContentS of HTML Containers

Michael J Hannah (
Wed, 20 Dec 1995 17:39:05 +0700

Date: Wed, 20 Dec 1995 17:39:05 +0700
Message-Id: <>
From: (Michael J Hannah)
Subject: Re: ContentS of HTML Containers

++ Date: Wed, 20 Dec 1995 15:02:14 -0500
++ From: "William C. Cheng" <>
++ (snip ... about
++ I tried the above URL and couldn't find any information about how to
++ read DTD.  Do you know of a specific URL for finding out about
++ %HTML.Highlighting?  Thanks!
++ --
++ Bill Cheng // Guest at Columbia Unversity Computer Science Department
++ william@CS.COLUMBIA.EDU      ...!{uunet|ucbvax}!!william
++ WWW Home Page: <URL:>

Reason not in HTML Reference
My document is intended as an alternative to reading the DTD.
You are correct that I do not refer to how to read DTD, and perhaps
I might add that to the acknowlegements, but it is really off topic.

Answer to the question you asked
The reference to the details of DTD, and how to read it (i.e. the
meaning of the syntax of DTD markup) can be found at:

Answer to the question you are implying
The RFC 1866 DTD includes syntax defining different option levels
of conformance.  It talks in section 1.2.3 about user agents that
may be a level one user agent or a level two user agent.  The option
identifies those aspects of the language that produce text highlighting,
which are features that may not be present in a minimal implementation
of a user browser (a simple text-only agent that has no capability
of bold, underline, etc.)  One can read the DTD assuming that this
text highlighting is available or not available.  A document that is
intended to be used by such a minimal browser would want to avoid using
some specific elements, and the DTD precisely defines which these would be.

Thus, with Highlighting the ENTITY text is defined as a set of possible
elements plus the entities phrase and font.  And these entities are in
turn also defined as part of Highlighting.

Without Highlighting, (note some lines later where the option of
%HTML.Highlighting terminates with the three characters "]]>" )
an alternate minimal definition of ENTITY text is given which does not
include the entities phrase and font.

For this same reason the ENTITY pre.content is defined twice, once
as part of the option HTML.Highlighting, and once minimally.

This capability to define options, and much more about the DTD syntax,
is described in the link I mentioned above.

Hope this answers what you really meant to ask.

Michael J. Hannah                         "Opinions are mine only,
Scientific Computing Systems               and will change without notice
Department 4918, Mail Stop 0807            whenever appropriate."

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