Nodes

In XPath, there are seven kinds of nodes: element, attribute, text, namespace, processing-instruction, comment, and document nodes.

XML documents are treated as trees of nodes. The topmost element of the tree is called the root element.

Look at the following XML document:

<?xml version="1.0" encoding="ISO-8859-1"?>
 
<bookstore>
  <book>
    <title lang="en">Harry Potter</title>
    <author>J K. Rowling</author>
    <year>2005</year>
    <price>29.99</price>
  </book>
</bookstore>

Example of nodes in the XML document above:

<bookstore> (root element node)
 
<author>J K. Rowling</author> (element node)
 
lang="en" (attribute node)

Atomic values

Atomic values are nodes with no children or parent.

Example of atomic values:

J K. Rowling

"en"

Items

Items are atomic values or nodes.