Using the Default Style Sheet
If an XML document does not contain a valid style sheet processing instruction, Microsoft® Internet Explorer displays the XML as an expanding and collapsing tree.
This tree view of the XML data is a convenient way to check that your XML is well-formed. To check a document, simply open the file in Internet Explorer. If there are any errors caused by the XML data not being well-formed, Internet Explorer lists these errors, with their line numbers, onscreen.
You can also use Internet Explorer to check that your XSLT style sheets and XML Schema documents are well-formed.
Internet Explorer displays an XML document asynchronously. This means that it starts displaying the XML document before the document has been completely downloaded. If an error occurs toward the end of a long document, most of the document might already be onscreen before Internet Explorer inserts an error message. In this case, you might have to scroll to the bottom of the page to view the error message.
When displaying XML documents, Internet Explorer loads the specified document type definition (DTD) or XML Schema, but does not report validation errors.