Conditional processing in xslt is a not unlike conditional
processing in other well-known programming languages, although its
wrapped in the xml-syntax which we all love.
If statements
Simle if-statements are done using the <xsl:if> tags
Example:
<xsl:if select="$mystring != ''>
...
</xsl:if>
There is no else-statements, so in case you need that,
consider the choose/when construct.
Choose/when statements
In case you want to case
out using multiple conditions, you need the
choose/when construct.
Example:
<xsl:choose>
<xsl:when test="$mystring = ''">
...
</xsl:when>
<xsl:when test="$mystring = 'foo'">
...
</xsl:when>
<xsl:otherwise>
...
</xsl:otherwise>
</xsl:choose>