XSLT(19) document() Function to access external xml

node-set document(object,node-set?)

object Required. Defines an URI to an external XML document

node-set Optional. Used to resolve relative URI

Example:

<xsl:value-of select="document('celsius.xml')/celsius/result[@value=$value]"/>

NOTE: WHEN use this function, make sure you are in the server, opening the web page on the computer will not work, AND no error msg is posted.