HTML, CSS, and XML Technologies

While you are trying just to do the tasks in each week, it might be useful at this point to stop for a while, step back and look at what you have learned so far. The combination of HTML, CSS, XML, and XSL actually allows you to build complete web sites. Some people make a living just on these technologies and their creative combinations. In actuality a modern web site is a system allowing for presentation level (HTML and CSS) to be separated from the model/controller complexity that is usually on the server and deals with data processing and transformation. From this perspective, XML can serve (and often does) a role of a data store with possibility of moving data from databases to XML and back (we will use SML as such later). Server side XSLT is actually a programming language which can compete with other programming languages and is especially effective for data processing and transformations using XML.

Even such well developed programming language as Java (and some others) has constructs (after version 1.4) allowing to use XSLT instead of writing a similar program in Java. Although the most widespread use of XSLT is in preparing HTML out of other data sources and formats for delivery to the user devices so that they will need only a browser, other transformations (see w3schools examples) are possible  and even more exquisite ways of data processing. ASP systems also often use XSLT as well as it can be useful on its own on both: server and client sides.