The default XML parser for current versions of Internet Explorer is either MSXML 2.0 or MSXML 3.0. Internet Explorer currently does not ship with MSXML 4.0 or later as its default XML parser or XSL processor for applying style sheet templates. To use features of these versions of MSXML from within Internet Explorer you must use scripting, when an XML DOM object is instantiated using the appropriate version-specific ProgID.
For more information, see Initiate XSLT in a Script.