SGML DTD for Internet Explorer 2.0 Markup

April 1996

Mark Buckley
Microsoft Corporation

Download DTD sample files (zipped, 8.31K).

Formally, hypertext markup language (HTML) is an application of standard generalized markup language (SGML)--that is, HTML follows the rules of the international SGML standard (ISO 8879). An SGML language is specified in large part by a document type definition (DTD) that defines the tags an author may use to mark up a document. W3C and IETF have published an SGML DTD for HTML 2.0.

Microsoft Internet Explorer supports table markup and other extensions to the basic markup found in HTML 2.0. The attached files comprise an SGML DTD that describes valid HTML markup for Microsoft Internet Explorer 2.0, including these extensions.

The principal file, IEHTML.DTD, defines markup for HTML headers and document bodies.
The IETABLES.DTD file contains table markup.
The IEHTML-S.DTD file invokes "strict" HTML markup.

The DTD for Internet Explorer 2.0 has been derived directly from the IETF draft DTD for HTML 2.0

, dated September 1995. All Internet Explorer 2.0 extensions as well as many Netscape Navigator extensions have been added to the DTD. The DTD for tables has been derived directly from the table markup portion of IETF's now expired draft DTD for HTML 3.0

, dated March 1995.

The DTD defines, first of all, HTML that works with Internet Explorer. That is, if your HTML document parses according to this DTD, it should be handled correctly by Internet Explorer 2.0.

Moreover, the DTD describes the "intentions" of Internet Explorer. Because Internet Explorer is designed to be very accepting, it's quite possible to write HTML that does not conform to this DTD but that will display acceptably in Internet Explorer anyway. We recommend, however, that HTML documents created for use with Internet Explorer do follow the grammar defined in the DTD to allow for more predictable results as both HTML and Internet Explorer continue to evolve.

Caveats

The DTD contains some Netscape extensions (for example, the NOSHADE attribute for <HR> that Internet Explorer does not support), as well as some table markup attributes (e.g., COLSPEC) that appear in the IETF HTML 3.0 Tables DTD, but that Internet Explorer does not support. Because we do not want HTML containing such markup to be rejected by a validating parser, we have included them in the DTD with comments.

This is a beta DTD. We expect some bugs. We also expect some disagreements about coding strategies for some of the more problematic aspects of the markup, for example, how to code the <CENTER> element. We encourage comments; please e-mail www-html@w3.org, Chris Wilson (cwilso@microsoft.com), or Mark Buckley (mbuckley@microsoft.com).