XML in a Nutshell, 3rd Edition

Chapter 13. Cascading Style Sheets (CSS)

The names of most elements describe the semantic meaning of the content they contain. Often, however, this content needs to be formatted and displayed to users. For this to occur, there must be a step where formatting information is applied to the XML document, and the semantic markup is transformed into presentational markup. There is a variety of choices for the syntax of this presentation layer. However, two are particularly noteworthy:

• Cascading Style Sheets (CSS)

• XSL Formatting Objects (XSL-FO)

CSS is a non-XML syntax for describing the appearance of particular elements in a document. CSS is a very straightforward language; no transformation is performed. The parsed character data of the document is presented more or less exactly as it appears in the XML document, although, of course, you can always transform the document with XSLT and then apply a CSS stylesheet to it if you need to rearrange the content of a document before showing it to the user. A CSS stylesheet does not change the markup of an XML document at all; it merely applies styles to the content that already exists.

By way of contrast, XSL-FO is a complete XML application for describing the layout of text on a page. It has elements that represent pages, blocks of text on the pages, graphics, horizontal rules, and more. You do not normally work with this application directly. Instead, you write an XSLT stylesheet that transforms your document’s native markup into XSL-FO. The ...