HTML DTDs (and other public text)

HTML is an application of SGML (Standard Generalized Markup Language), because SGML is an open standard that facilitates structured documents. Unlike LaTeX, troff, or RTF, SGML has no universal "tag set." In stead, each application of SGML defines its own tags in a DTD, or Document Type Definition. An SGML DTD rigoriously specifies the structure of a type of document. For example, the HTML 2.0 DTD specifies that a document has a HEAD and a BODY; the HEAD contains a TITLE, and the BODY contains H1, H2, P, ADDRESS, elements, and so on.

HTML Dialects: Features, Extensions, and DTDs

A number of HTML extensions have been proposed in various HTML discussion forums. Unfortunately, some of them have been deployed without accompanying documentation in the form of a DTD.

DTDs (especially DTD modules, see below) describing those features are solicited. Please send them to www-html, or html-wg.

Newest first:

experimental HTML DTD July 96

including style sheets, scripting, the object tag, internationalization and some extensions to forms.

HTML 3.2 May 1996

In pre-release form

Inserting objects into HTML3 Working Draft 22 Apr 96

Dave Raggett et. al.

The HTML3 Table Model W3C Working Draft 23-Jan-96

@@link to DTD

A Modular DTD Approach for HTML Specification In Progress: Jan 19, 1996

Murray Altheim <murray@stonehand.com>

Internationalization of the Hypertext Markup Language Internet Draft 7 Feb 1996

F. Yergeau, G. Nicol, G. Adams, M. Duerst.

I18N DTD
the SGML declaration
the enlarged Latin-1 entity set
a diff showing the changes from HTML 2.0.
background materials by F. Yergeau

Netscape SCRIPT tags Jan 1996?

Netscape Navigator 2.0beta3 adds SCRIPT element and attribute, plus onclick etc. attributes.

A Proposed Extension to HTML : Client-Side Image Maps Internet Draft 01 Dec 1995

James L. Seidman, Spyglass

@@ DTD fragment?

Form-based File Upload in HTML, Experimental RFC, November 1995

E. Nebel and L. Masinter, Xerox

@@ link to DTD fragment

DTD for Netscape Frames markup In Progress: 20 Sep 1995.

Joe English, Note that this is not a Netscape-supplied document.

frames.dtd, the Frames Document Type Definition.
catalog, an SGML Open TR9401 style catalog entry for the DTD.
alexed.html, a modified (validated) copy of Alex Edelstein's home page, which references the new DTD (and with other markup errors corrected).
test.html, another example FRAMES document, taken from the proposal posted to www-html and html-wg.

Netscape extensions to HTML 3.0

@@Netscape 2.0? extensions: HTML3 tags like BIG, SMALL, plus FONT FACE

Microsoft Internet Explorer 1.0 HTML extensions 1995 (exact date unknown)

LOWSRC

@@ Is this documented anywhere? Netscape?

X-ALTSRC

@@Who's is this?

Bulletin

@@ Firstfloor

HTML 2.0 November, 1995 IETF Proposed Standard

This is the public text that appears in RFC1866.

The full DTD, and Strict version
Level 1 features, and Strict version
ISO Added Latin 1 entity set
SGML Declaration
catalog Sample SGML Open style Entity Catalog
1995-09-22 distribution: all of the above in a tarball.
changelog of html.dtd from 1992/12/03 thru publication of RFC1866.

HotJava DTD 24 July 1995

I have taken the HTML 3.0 DTD dated 16 Mar 95 and added the APP element introduced by Sun Microsystems Corp. to accomodate their Java/HotJava WWW application environment.
Revisions made by: Mark Gaither (markg@hal.com)
Original Author: Dave Raggett <dsr@hplb.hpl.hp.com>

full DTD, based on HTML 3.0 with Java APP tag.

Mozilla DTD 27 Oct. 1994

Mark Gaither and Dan Connolly

full DTD, based on HTML 2.0 with some Netscape 1.1 extensions.

Netscape EXTENSIONS TO HTML 2.0 1994 (exact date unknown)

These extensions were instruduced in the Netscape 1.1 beta releases.

HTML 3.0 Expired

Mosaic for X version 2.0 Fill-Out Form Support

introduction of FORMS into HTML

Imagemaps

new idiom: <A href=xxx><IMG ISMAP></a>

IMG

HTML 1.0 DTD March 1993

About HTML

@@ TimBL's original spec. Still available?

What is a DTD good for?

First and foremost, it codifies an agreement among the community about the structure of documents -- in this case, HTML documents.

Additionally, it allows us to:

Validate that a document has no syntactic or structural errors
Visualize the document structure. (I'd like to see this made into a web service as well!)
Convert to and from HTML in an automated fashion with confidence

Aids to Understanding

SGML syntax is somewhat obscure, but at the end of the day, it's pretty similar to a context-free grammar. If you're a programmer, you probably deal with CFGs all the time (you may know them as BNF grammars, or railroad-diagrams, but they're all the same). If you're not a programmer, you deal with CFGs all the time, but it's subconscous! See:

SGML and the Web: especially: Robin Cover's edited collection of SGML materials
perlsgml: @@This is an analysis of the HTML 2.0 DTD maintained by Earl Hood. It does a better job of showing inclusion and exclusion exceptions than the reference above. It's a bit out of date, last I checked.

To compund matters, HTML is evolving continuously. It's a super-human job to keep track of it all. For one pretty good attempt, see:

HTML Reference Manual In progress: 2 January 1996: Michael J. Hannah, Sandia National Laboratories mjhanna@sandia.gov

Daniel W. Connolly
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