Max xml attribute .::RESOLVED::.

Is there a way I can get the maximum value of a given attribute in an xml file using xpath?

Eg. if I wanted the max "id"

<root>
<subject>
<message id="2"/>
<message id="4"/>
<message id="8"/>
</subject>
<subject>
<message id="5"/>
</subject>
</root>

would return "8".


Thanks.

Figured it out.
Here's the code for anyone who wants it....


<xsl:variable name="maxMessageID">
<xsl:for-each select="/root/subject/message">
<xsl:sort data-type="number" order="descending" select="@id"/>
<xsl:if test="position()=1">
<xsl:value-of select="@id"/>
</xsl:if>
</xsl:for-each>
</xsl:variable>