2. Introduction to HTML

HTML, or HyperText Markup Language is designed to specify the logical organisation of a document, with important hypertext extensions. It is not designed to be the language of a WYSIWYG word processor such as Word or WordPerfect. This choice was made because the same HTML document may be viewed by many different "browsers", of very different abilities. Thus, for example, HTML allows you to mark selections of text as titles or paragraphs, and then leaves the interpretation of these marked elements up to the browser. For example one browser may indent the beginning of a paragraph, while another may only leave a blank line.

HTML instructions divide the text of a document into blocks called elements. These can be divided into two broad categories -- those that define how the BODY of the document is to be displayed by the browser, and those that define information `about' the document, such as the title or relationships to other documents. The vocabulary of these elements and a description of the overall design of HTML documents is given in the rest of Section 2. The Last part of the section also describes standard naming schemes for HTML documents and related files.

The detailed rules for HTML (the names of the tags/elements, how they can be used) are defined using another language known as the standard generalized markup language, or SGML. SGML is wickedly difficult, and was designed for massive document collections, such as repair manuals for F-16 fighters, or maintenance plans for nuclear submarines. Fortunately, HTML is much simpler!

However, SGML has useful features that HTML lacks. For this reason, markup language and software experts have developed a new language, called XML (the eXtensible markup language) which has most of the most useful features of HTML and SGML.