Chapter 1. Essential XML

Welcome to the world of Extensible Markup Language, XML. This book is your guided tour to that world, so have no worriesyou've come to the right place. That world is large and expanding in unpredictable ways every minute, but we're going to become familiar with the lay of the land in detail here. And there's a lot of territory to cover because XML is getting into the most amazing places, and in the most amazing ways, these days.

XML is a language defined by the World Wide Web Consortium (W3C, www.w3c.org), the body that sets the standards for the Web, and this first chapter is all about getting a solid overview of that language and how you can use it. For example, you probably already know that you can use XML to create your own elements, thus creating a customized markup language for your own use. In this way, XML supercedes other markup languages such as Hypertext Markup Language (HTML); in HTML, all the elements you use are predefinedand there are not enough of them. In fact, XML is a metamarkup language because it lets you create your own markup languages.