Web Design in a Nutshell, 3rd Edition

Style Sheets and XML

A markup language describes only the structure of a document; it is not concerned with how it looks. Like HTML, XML documents can use Cascading Style Sheets for presentation. In fact, the CSS Level 2 Recommendation has been broadened for use with all XML applications, not just web documents. CSS is covered in Part III of this book.

Another style sheet language called the Extensible Stylesheet Language (XSL) exists for XML documents. XSL creates a large overhead in processing, whereas CSS is fast and simple, making it generally preferable.

XSL is useful when the contents of the XML document need to be “transformed” before final display. Transforming generally refers to the process of converting one XML language to another, such as turning a particular XML language into XHTML on the fly, but it can also be used for transformations as simple as replacing words with other words. An Extensible Stylesheet Language for Transformations(XSLT, a subset of XSL) style sheet works as a translator in the transformation process. XSL is not covered in this chapter; for more information, see the XSL information on the W3C site at http://www.w3.org/Style/XSL/.