HTML 4.01 Overview

The HTML 4.01 Recommendation (1999) is the best established and supported HTML specification as of this writing.

Three Versions of HTML 4.01

Both the HTML 4.01 and XHTML 1.0 Recommendations encompass three slightly different specification documents, called Document Type Definitions (or DTDs). DTDs define every element, attribute, and entity along with the rules for their use. The three versions are:

Transitional DTD
Includes all deprecated elements and attributes in order to be backward compatible with the legacy behavior of most browsers. Deprecated elements and attributes are permitted but discouraged from use.
Strict DTD
Excludes all elements and attributes that have been deprecated to reinforce the separation of document structure from presentation.
Frameset DTD
Includes the same elements as the Transitional DTD with the addition of elements for creating framed web pages (frameset, frame, and noframe). The Frameset DTD is kept separate because the structure of a framed document (where frameset replaces body) is fundamentally different from regular HTML documents.

Document Structure

This markup sample shows the minimal structure of an HTML 4.01 document.

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"   "http://www.w3.org/TR/html4/strict.dtd">
    <title>Document Title</title>
    Content of document ...

The first line is the DOCTYPE Declaration that indicates this document uses the Strict HTML 4.01 DTD. For a complete list of declarations, see the DOCTYPE Declarations page.