Introduction.

Shared Skills are firmly committed to using the X technologies of XML and XSL as part of our web site development. The following few paragraphs will shed a little light on the benefits we gain from these technologies.

XML, structure and the Internet.

Take a look at a few pages on the Internet. The common factor with most of these pages is that they are visually attractive, often with exciting animations and interactivity. Which all said and done is great. The problem is that behind these pretty pages is huge amounts of program code with the real data almost impossible to find. If you are feeling brave, view the source of this page from your browser. These words are in there somewhere!

"So what?" I hear you ask. Well, there are two huge problems with this approach. The first is that it makes it very hard for those hard working search engines to locate the real meaning of the data. The second is that it is difficult and expensive to modify the pages.

XML

XML solves many of these problems, it's been designed to convey data from machine to machine with ease. Search engines can or will be able to understand it and it's relatively easy to maintain.
the trouble is, it looks like this:

<xsl:template match="Description">
  <meta Name="description" >
    <xsl:attribute name="content">
      <xsl:apply-templates/>
    </xsl:attribute> 
  </meta> 
</xsl:template>

Which, let's face it is all rather unpleasant.

Creating the page:

This is where XSL comes in, the other of our X technologies. XSL provides a mechanism for converting XML into HTML so that you and I can read it. The sample code above is actually XSL (which is a dialect of XML). Specifically, it is part of the XSL document that was used to create this page.

The process of combining XML and XSL to create HTML takes place on the client (browser), or the server, or alternatively offline somewhere. This page was generated on my machine and then uploaded to the web server.

The Benefits:

There will we feel be many long-term benefits of using XML, mainly due to storing raw page data in an open and machine readable form. Unlike other data formats, it is unlikely to disappear (consider whether you can read a Wordstar file from 10 years ago on your machine today!).

Better than that, we are getting huge benefits right. Suppose I decide to add another page to this site, naturally, I want to create a button for it and link from every page. Using conventional HTML techniques, it would take an hour or so to change all the pages on the site. Using XSL, I just change the master XSL document and regenerate all the pages. Total time: less than 5 minutes!

The other big benefit comes in the creation of dynamic pages from a database. Our catalogue solution extracts data from a database as XML and then dynamically creates HTML from it. We get almost infinite flexibility in page layout and all with open standards. See the catalogue at Yacht Parts for an example of this technique in use.

References

• XSL and XML resources from James Clark.
• The Simple API for XML
• XSL specifications at W3C
• XML specifications at W3C
• Another example of a web site generated using these technologies.

For more information on the generation of web pages using these technologies contact Shared Skills.