The select attribute selects only the first node that matches its
selection _criterion. What if you have multiple nodes that could
match? For example, say that you can have multiple <NAME>
elements for each planet:
<PLANET>
<NAME>Mercury</NAME>
<NAME>Closest planet to the
sun</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><!--At perihelion-->
</PLANET>
The <xsl:value-of> element's select attribute by itself will
select only the first <NAME> element; to loop over all possible
matches, you can use the <xsl:for-each> element like this:
<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="PLANETS">
<HTML>
<xsl:apply-templates/>
</HTML>
</xsl:template>
<xsl:template match="PLANET">
<xsl:for-each select="NAME">
<P>
<xsl:value-of select="."/>
</P>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
This style sheet will catch all <NAME> elements, place their
values in a <P> element, and add them to the output document,
like this:
<HTML>
<P>Mercury</P>
<P>Closest planet to the
sun</P>
<P>Venus</P>
<P>Earth</P>
</HTML>
We've seen now that you can use the match and select attributes to
indicate what nodes you want to work with. The actual syntax that you
can use with these attributes is fairly complex but worth knowing.
I'll take a look at the match attribute in more detail first, and
I'll examine the select attribute later in this chapter.
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