This chapter focuses on dealing with various types of information that can be presented within a document. To develop your ability to write conforming, sophisticated documents, it's important to examine the types of key data and how that data is used in HTML and XHTML syntax. Uniform Resource Identifiers (URIs), colors, lengths, language codes, link types, and so forth are governed by a variety of rules and methodologies set forth in the given language and language version specification.
The W3C provides data management information in its specifications so that browser developers and software manufacturers can produce software that conforms to the specification and so that you, the Web author, can understand how data is typed and processed. As you are by now aware, this information has often been overlooked or mismanaged by browser and software manufacturers as well as Web authors.