If you want to locate a specific piece of information in an XML document, then it can be a bit of a hassle to navigate the nodes of the DOM tree. The XPath language makes it simple to access tree nodes. For example, suppose you have this XML document:
<configuration> . . . <database> <username>dbuser</username> <password>secret</password> . . . </database> </configuration>
You can get the database user name by evaluating the XPath expression
That's a lot simpler than the plain DOM approach:
Get the document node.
Enumerate its children.
Locate the database element.
Get its first child, the username element.
Get its first child, a Text node.
Get its data.
An XPath can describe a set ...