WebReference.com - Excerpt from Inside XSLT, Chapter 2, Part 2 (2/5)

Inside XSLT

In practice, <?xsl:stylesheet?> is used mostly with browsers, because with standalone processors, you usually give the name of the stylesheet document directly, as when you use the Oracle XSLT processor this way:

C:\planets>java oracle.xml.parser.v2.oraxsl planets.xml planets.xsl planets.html

In fact, it may surprise you to learn that <?xsl:stylesheet?> is not part of the XSLT recommendation. This processing instruction has its own recommendation just for itself, which you can find at www.w3c.org/TR/xml-stylesheet. Among other things, this means that XSLT processors are not obliged to support this processing instruction, and most standalone processors do not.

Here's an example. In Chapter 1, you saw planets.xml, a well-formed XML document that holds data about three planets: Mercury, Venus, and the Earth. You can use the <?xml-stylesheet?> processing instruction in planets.xml to indicate what XSLT stylesheet to use, where you set the type attribute to "text/xml" (W3C also allows "application/xml", and the Internet Explorer requires "text/xsl") and the href attribute to the URI of the XSLT stylesheet, such as planets.xsl:

Listing 2.1: planets.xml

<?xml version="1.0"?> <?xml-stylesheet type="text/xml" href="planets.xsl"?> <PLANETS> <PLANET> <NAME>Mercury</NAME> <MASS UNITS="(Earth = 1)">.0553</MASS> <DAY UNITS="days">58.65</DAY> <RADIUS UNITS="miles">1516</RADIUS> <DENSITY UNITS="(Earth = 1)">.983</DENSITY> <DISTANCE UNITS="million miles">43.4</DISTANCE> </PLANET> <PLANET> <NAME>Venus</NAME> <MASS UNITS="(Earth = 1)">.815</MASS> <DAY UNITS="days">116.75</DAY> <RADIUS UNITS="miles">3716</RADIUS> <DENSITY UNITS="(Earth = 1)">.943</DENSITY> <DISTANCE UNITS="million miles">66.8</DISTANCE> </PLANET> <PLANET> <NAME>Earth</NAME> <MASS UNITS="(Earth = 1)">1</MASS> <DAY UNITS="days">1</DAY> <RADIUS UNITS="miles">2107</RADIUS> <DENSITY UNITS="(Earth = 1)">1</DENSITY> <DISTANCE UNITS="million miles">128.4</DISTANCE> </PLANET> </PLANETS>

That's how to use the <?xml-stylesheet?> element; now it's time to start working on writing the stylesheet itself. I'll do that by creating planets.xsl.