Checking a very simple w3schools example here: it works in every browser i tried (Even IE6!)

I'll admit my knowledge is basic, but I like the idea because it separates data from presentation.

Is it a realistic option to have a web site using xml/xsl? If so, why aren't people using it.

In theory, I can have my site layout in XSL, and use it to transform an XML document with the page content, title. Does this work in practice?

If so, how are the documents styled? CSS? I thought XSL had its own style rules, but that example seems to use CSS.

Is javascript supported?