In the previous chapter I explained how XSL can be used to transform a document
from XML to HTML. The trick was to add an XSL stylesheet information to the XML
file, and to let the browser do the transformation.
Even if this works fine, it is not always desirable to include a stylesheet reference in the
XML file, and the solution will not work in a non XML aware browser.
A much more versatile solution would be to use a JavaScript to do the XML to
HTML transformation.
By using a JavaScript we are more open for these possibilities:
Allowing the JavaScript to do browser specific testing
Using different style sheets according to browser and/or user
needs
That's the beauty of XSL. One of the design goals for XSL was to make it possible to
transform data from one format
to another, supporting different browsers and different user needs.
XSL transformation on the client side is bound to be a major part of the
browsers work tasks in the future, as we will se a growth in the specialized
browser marked (think:
Braille, Speaking Web, Web Printers, Handheld PCs, Mobile Phones .....).
The XML file and the XSL file
Take a new look at the XML document that you saw in the previous chapter (or
open it with IE5):
The syntax of the above XSL document was explained in the previous chapter,
so it will not be explained here. But be sure to notice that the XML file does
not have a reference to the XSL file, and the XSL file does not have a reference
to the XML file.
IMPORTANT: The above sentence indicates that an XML file could
be transformed using many different XSL files.
Transforming XML to HTML on the client
Here is the simple source code needed transform the XML file to HTML on the
client (try it yourself):
<html>
<body>
<script language="javascript">
// Load XML
var xml = new ActiveXObject("Microsoft.XMLDOM")
xml.async = false
xml.load("cd_catalog.xml")
// Load the XSL
var xsl = new ActiveXObject("Microsoft.XMLDOM")
xsl.async = false
xsl.load("cd_catalog.xsl")
// Transform
document.write(xml.transformNode(xsl))
</script>
</body>
</html>
The first block of code creates an instance of the Microsoft XML parser
(XMLDOM), and loads the XML document into memory. The second block of code creates
another instance of the parser and loads the XSL document into memory. The last
line of code transforms the XML document using the XSL document, and writes the
result to the HTML document.