XML is a subset of a family of 'markup languages'. This family includes HTML, XHTML, MathML and other markup languages, which are being created at a phenomenal rate.

All of these markup languages are derivatives of the Standard Generalised Markup Language, or SGML. To locate the syntax of these standards, have a look at the World Wide Web Consortiums's (W3C) website at www.w3.org. Here you will find not only the current standards, but draft specifications for new markup languages.

If you're serious about learning XML, you should keep checking this resource.

It's quite easy to write an XML document. First of all you must declare the standard that the document will comply with. Then you make a statement. Here's what it might look like:

<?xml version 1.0 ?>

<statement>This is my statement<statement>

The key thing here is that we can see that the document contains a statement, as the content is surrounded by an 'element' named statement. As you will see later on, elements are themselves surrounded by angle brackets.

We refer to such a document as being human readable, because we can read the XML file and make sense of it.

However, the power of XML is such that by creating our own elements (in angle brackets), we can make a document machine readable. To get started, let's look at a markup language we are all aware of: HTML.