1 About the HTML 4.0 Specification

This document has been written with two types of readers in mind: HTML authors and HTML implementors. We hope the specification will provide authors with the tools they need to write efficient, attractive, and accessible documents, without over-exposing them to HTML's implementation details. Implementors, however, should find all they need to build user agents that interpret HTML correctly.

The specification has been written with two modes of presentation in mind: electronic and printed. Although the two presentations will no doubt be similar, readers will find some differences. For example, links will not work in the printed version (obviously), and page numbers will not appear in the electronic version. In case of a discrepancy, the electronic version is considered the authoritative version of the document.

1.1 How to read the specification

The specification may be approached in several ways:

• Read from beginning to end. The specification begins with a general presentation of HTML and becomes more and more technical and specific towards the end. This is reflected in the specification's main table of contents, which presents topical information, and the indexes, which present lower level information in alphabetical order.

• Quick access to information. In order to get information about syntax and semantics as quickly as possible, the electronic version of the specification includes the following features:
  1. Every reference to an element or attribute is linked to its definition in the specification.
  2. Every page will include links to the indexes, so you will never be more than two links away from finding the definition of an element or attribute.

  3. The front pages of the three sections of the language reference manual extend the initial table of contents with more detail about each section.

1.2 How the specification is organized

This specification includes the following sections:

Sections 2-3: Introduction to HTML 4.0

The introduction gives an overview of what can be done with HTML 4.0 and provides some design tips for developing good HTML habits.

The brief SGML tutorial gives readers some understanding of HTML's relationship to SGML and gives summary information on how to read the HTML Document Type Definition (DTD).

Sections 4 - 25: HTML 4.0 reference manual

The bulk of the reference manual consists of the HTML language reference, which defines all elements and attributes of the language.

This document has been organized by topic rather than by the grammar of HTML. Topics are grouped into three categories: structure, presentation, and interactivity. Although it is not easy to divide HTML constructs perfectly into these three categories, the model reflects the designers' experience that separating a document's structure from its presentation produces more effective and maintainable documents.

The language reference consists of the following information:

• Conventions used by the editors of this specification.

• How Uniform Resource Locators (URL) play a role in HTML.

• What characters may appear in an HTML document.

• Basic data types of an HTML document.

• Elements that govern the structure of an HTML document, including text, lists, tables, links, and included objects, images, and applets.

• Elements that govern the presentation of an HTML document, including style sheets, fonts, colors, rules, and other visual presentation, and frames for multi-windowed presentations.

• Elements that govern interactivity with an HTML document, including forms for user input and scripts for active documents.

• The SGML definition of HTML, including the SGML declaration of HTML, the HTML DTD, and the list of character entities.

Appendixes

The appendix contains information about changes from HTML 3.2 and performance and implementation notes.

References

Indexes

Two indexes give readers rapid access to the definition of all elements and attributes The indexes also summarize some key characteristics of each element and attribute.

1.3 Acknowledgments

Thanks to everyone who has helped to author the working drafts that went into the HTML 4.0 specification, and all those who have sent suggestions and corrections. A particular thanks to T.V. Raman (Adobe) for his work on improving the accessibility of HTML forms for people with disabilities.

The authors of this specification, the members of the W3C HTML Working Group, deserve much applause for their diligent review of this document, their constructive comments, and their hard work: John D. Burger (MITRE), Steve Byrne (JavaSoft), Martin J. Dürst (University of Zurich), Daniel Glazman (EDF), Scott Isaacs (Microsoft), Murray Maloney (GRIF), Steven Pemberton (CWI), Jared Sorensen (Novell), Powell Smith (IBM), Robert Stevahn (HP), Ed Tecot (Microsoft), Jeffrey Veen (HotWired), Mike Wexler (Adobe), Misha Wolf (Reuters), and Lauren Wood (SoftQuad).

Thank you Dan Connolly (W3C) for thoughtful input and guidance as chairman of the HTML working group. Thank you Sally Khudairi (W3C) for your indispensable work on the press release.

Of particular help from the W3C at Sophia-Antipolis were Janet Bertot, Bert Bos, Stephane Boyera, Daniel Dardailler, Yves Lafon, Håkon Lie, Chris Lilley, and Colas Nahaboo from Bull.

Lastly, thanks to Tim Berners-Lee without whom none of this would have been possible.