The HTML 4.01 Recommendation (1999) is the best established and supported HTML specification as of this writing.
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:
noframe). The Frameset DTD is kept separate because the structure of a framed document (where
body) is fundamentally different from regular HTML documents.
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">
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.