18.0.0- An Introduction to XML

An Introduction to XML

Over the past couple of years, the acronym XML, which stands for Extensible Markup Language, has been cropping up with increasing frequency. As it has gained more coverage, the spin-doctors have been out in force, claiming that it will solve all manner of programming problems. While some of these claims have yet to be implemented, there are certainly some very strong reasons why you should be learning it, not least that it could just make your life a lot easier.

The first thing to make clear is that, assuming you are familiar with HTML, XML offers a new way of tagging (or marking up) your data that is so straight forward you will wonder why it is making such big waves. Yet, while HTML and XML may look very similar, they are in fact quite different.

In this chapter we will see what all the fuss is about. It will introduce XML and get you used to writing XML, styling XML for the Web, and how to access and manipulate data in an XML document. It will also cover some of the advantages to using XML in your web development, and how ASP helps harness the benefits of XML.

So in this chapter we will see:

• Some background to help us understand the importance of XML
• What XML is and how to write an XML document
• Some of the associated specifications surrounding XML
• How to style XML for display in a browser
• How to get details from an XML file using the Document Object Model
• How to create an XML document on the server
• How to create XML documents from a web page
• How to create XML from a relational database
• How to use IE5 to display and navigate through XML documents

Before we dive into using XML and showing you how it can be used, it would be helpful to have a quick look at markup languages in general, what markup is, and the history that has lead to XML.