Chapter 1. The XML Galaxy

This chapter introduces you to XML. It tells you the why and what: why was XML developed, and what is XML good at? Before we turn to how to use XML, which is the topic of the next 11 chapters, you need to understand where XML might be of use for you.

In this chapter, you will learn the essential concepts behind XML:

• Which problems XML solves; in other words, what XML is good at.

• What a markup language is and what the relationship between XML, HTML, and SGML is.

• How and why XML was developed.

• Typical applications of XML, with examples.

• The benefits of using XML when compared to HTML. When is XML better than HTML?