Chapter 13. XSL Transformations

In this chapter, I'm going to start working with the Extensible Styles Language (XSL). XSL has two parts—a transformation language and a formatting language.

The transformation language lets you transform documents into different forms, while the formatting language actually formats and styles documents in various ways. These two parts of XSL can function quite independently, and you can think of XSL as two languages, not one. In practice, you often transform a document before formatting it because the transformation process lets you add the tags the formatting process requires. In fact, that is one of the main reasons that W3C supports XSLT as the first stage in the formatting process, as we'll see in the next chapter.

This chapter covers the transformation language, and the next details the formatting language. The XSL transformation language is often called XSLT, and it has been a W3C recommendation since November 11, 1999. You can find the W3C recommendation for XSLT at http://www.w3.org/TR/xslt.

XSLT is a relatively new specification, and it's still developing in many ways. There are some XSLT processors of the kind we'll use in this chapter, but bear in mind that the support offered by publicly available software is not very strong as yet. A few packages support XSLT fully, and we'll see them here. However, no browser supports XSLT fully yet.

I'll start this chapter with an example to show how XSLT works.