The XSLT Processor
The XSLT processor works with a source tree, applies a style sheet tree to the source tree, and produces a result tree. The source tree and the result tree are the XML DOM for the source XML file and the XSLT style sheet, respectively. The trees are produced by the MSXML parser.
The following illustration shows the processing relationship among the XSLT processor, XSLT tree, source tree, and result tree. Click on a colored area in the illustration to find out about that particular part of this relationship.