Introduction

If I had to hazard a guess, I would say that at least 60 percent of the HTML delivered over the Internet today is at least partially generated by code. This is not because HTML is painstakingly hard to write, as Tim Berners-Lee states in the opening quotation (it is, but now we have fancy HTML editors), but because dynamically generated HTML allows you to do so much more.

There are many open and proprietary technologies for delivering HTML content from data stored in other forms. However, when the data is in XML, XSLT is one of the most important tools of which web authors should be aware.

You can use XSLT to generate HTML in three basic ways.

First, XSLT can transform XML into HTML and statically store the generated HTML on a web server or hard drive for delivery to a browser. This is also a good way to test such transformations.

Second, you can use XSLT as a server-side scripting solution in which XML extracted from flat files or databases is dynamically transformed by the web server as requested by the client browser. This solution is necessary when the underlying data changes frequently. However, sometimes a hybrid solution is used in which HTML is constructed on demand, but then cached on the server to avoid the need for subsequent transformations as long as the underlying data does not change. If you wish to use XSLT server side, you should definitely take a look at Apache Cocoon (http://cocoon.apache.org).

Third, you can use XSLT as a client-side stylesheet, provided the browser supports XSLT processing. At this time, the latest versions of Microsoft Internet Explorer (Version 6.0 or later), Netscape Navigator (6.1 or later), Mozilla, Firefox, and Apple Macintosh Safari (Tiger) have support for XSLT right out of the box. Older versions of IE require installation of MSXML 3.0 in replacement mode. In addition, XSmiles (http://www.x-smiles.org/) and the Antenna House XSL Formatter (http://www.antennahouse.com/) perform client-side XSLT processing and display the result. XSmiles can handle all sorts of results, including SVG and XSL-FO, although the HTML handling is not perfect. The Antenna House XSL Formatter handles XSL-FO. As the state of the world changes rapidly in this area, you should check the latest online documentation of your favorite browser or browser add-in.