Scans document linearly and presents each item to the application only once. The application must save the data at this point
Converts the document's contents into a node tree that can be searched via the API
CDATA tags can be use to tell an XML parser to ignore anything inside them. This can be particularly useful when you want a parse to ignore badly formed (not XHTML) HTML. The start CDATA tag is <![CDATA[ and the end one is ]]> e.g.
<sometag> <![CDATA[ <br><img src="someimage.gif"> ]]> </sometag>