What is XML?

Okay, we’re going to take a big step back, for a page or two, and look at XML (not to be confused with XHTML). This is going to be a fast ride, so hang on...

Let’s use HTML for comparison. With HTML you’re basically told what elements you can and can’t use, right? So, if you want to just make up an element, like <cool>, to wrap around content, you can’t do it, can you? Ah, but with XML, you can. If fact, you can invent totally new markup languages using XML. Let’s look at an example: