XML DOM Nodes

Each component in an XML document is a node.

Node

According to DOM, each component in an XML document is aNode.

DOM is defined as follows:

  • The entire document is a document node
  • Each XML tag is an element node
  • The text contained within an XML element is a text node
  • Each XML attribute is an attribute node
  • Comments are comment nodes

DOM instance

Please see the following XML file (books.xml):

<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book category="children">
  <title lang="en">Harry Potter</title> 
  <author>J K. Rowling</author> 
  <year>2005</year> 
  <price>29.99</price> 
</book>
<book category="cooking">
  <title lang="en">Everyday Italian</title> 
  <author>Giada De Laurentiis</author> 
  <year>2005</year> 
  <price>30.00</price> 
</book>
<book category="web">
  <title lang="en">Learning XML</title> 
  <author>Erik T. Ray</author> 
  <year>2003</year> 
  <price>39.95</price> 
</book>
<book category="web">
  <title lang="en">XQuery Kick Start</title> 
  <author>James McGovern</author> 
  <author>Per Bothner</author> 
  <author>Kurt Cagle</author> 
  <author>James Linn</author> 
  <author>Vaidyanathan Nagarajan</author> 
  <year>2003</year> 
  <price>49.99</price> 
</book>
</bookstore>

In the above XML, the root node is <bookstore>. All other nodes in the document are contained within <bookstore>.

The root node <bookstore> has four <book> nodes.

The first <book> node has four nodes: <title>, <author>, <year>, and <price>, each of which contains a text node, "Harry Potter", "J K. Rowling", "2005", and "29.99".

Text is always stored in the text node

A common error in DOM processing is to think that the element node contains text.

However, the text of the element node is stored in the text node.

In this example:<year>2005</year>, the element node <year> has a text node with the value "2005".

"2005" Not The value of the <year> element!