I have a limitation to use MSXML 3.0 only as a XSLT processor but I
want to get a URI or full path of source xml document that is being
processed. Using Saxon or using XSLT 2.0, I can get it using
document-uri(.). But, I don't seem to be able to find way to get it
with limited MSXML 3.0 functions.

Can somebody provide help on how to achieve it?

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
	xmlns:msxsl="urn:schemas-microsoft-com:xslt"
	xmlns:js="http://example.com/js"
	exclude-result-prefixes="msxsl js"
	version="1.0">
	
	<msxsl:script language="JScript" implements-prefix="js">
		function documentUri(nodeSet) {
			var node = nodeSet.item(0);
			return node.nodeType === 9 ? node.url : node.ownerDocument.url;
		}
	</msxsl:script>
	
	<xsl:output indent="yes"/>
	
	<xsl:template match="/">
		<results>
			<result>
				<xsl:value-of select="js:documentUri(/)"/>
			</result>
			<result>
				<xsl:value-of select="js:documentUri(/*)"/>
			</result>
		</results>
		
	</xsl:template>
</xsl:stylesheet>