Selecting Xml Nodes in MSXML 3 via XPath
Apparently, you need to set the SelectionLanguage property of a JavaScript XML Document object to XPath so you can select nodes via XPath.
var xmldoc = new ActiveXObject("Microsoft.XMLDOM");
// or var xmldoc = new ActiveXObject('Msxml2.DOMDocument.3.0');
xmldoc.async = "false";
xmldoc.loadXML(xmlData);
xmldoc.setProperty("SelectionLanguage", "XPath");
After which you can use XPath to select nodes. This is inevitable for MSXML 3.
Read the complete post at http://alexrazon.blogspot.com/2006/11/selecting-xml-nodes-in-msxml-3-via.html