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Table of contents
XML DOM Tutorial
DOM Introduction
DOM Nodes
DOM Node Tree
DOM Parsing
DOM Load Function
DOM Methods
DOM Accessing
DOM Node Info
DOM Node List
DOM Traversing
DOM Browsers
DOM Navigating

Manipulate Nodes
DOM Get Values
DOM Change Nodes
DOM Remove Nodes
DOM Replace Nodes
DOM Create Nodes
DOM Add Nodes
DOM Clone Nodes
DOM HttpRequest

XML DOM Reference
DOM Node Types
DOM Node
DOM NodeList
DOM NamedNodeMap
DOM Document
DOM DocumentImpl
DOM DocumentType
DOM ProcessingInstr
DOM Element
DOM Attribute
DOM Text
DOM Comment
DOM HttpRequest
DOM ParseError Obj
DOM Parser Errors

DOM Summary

DOM Examples
DOM Validator

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XML DOM - Navigating Nodes

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Nodes can be navigated using node relationships.


The examples below use the XML file books.xml.
A function, loadXMLDoc(), in an external JavaScript is used to load the XML file.

Get the parent of a node
This example uses the parentNode property to get the parent of a node

Get the first child element of a node
This example uses the firstChild() method and a custom function to get the first child node of a node

Navigating DOM Nodes

Accessing nodes in the node tree via the relationship between nodes, is often called "navigating nodes".

In the XML DOM, node relationships are defined as properties to the nodes:

  • parentNode
  • childNodes
  • firstChild
  • lastChild
  • nextSibling
  • previousSibling

The following image illustrates a part of the node tree and the relationship between nodes in books.xml:

Node tree

DOM - Parent Node

All nodes has exactly one parent node. The following code navigates to the parent node of <book>:


Example explained:

  1. Load "books.xml" into xmlDoc using loadXMLDoc()
  2. Get the first <book> element
  3. Output the node name of the parent node of "x"

Try it yourself

Avoid Empty Text Nodes

Firefox, and some other browsers, will treat empty white-spaces or new lines as text nodes, Internet Explorer will not.

This causes a problem when using the properties: firstChild, lastChild, nextSibling, previousSibling.

To avoid navigating to empty text nodes (spaces and new-line characters between element nodes), we use a function that checks the node type:

function get_nextSibling(n)
while (y.nodeType!=1)
return y;

The function above allows you to use get_nextSibling(node) instead of the property node.nextSibling.

Code explained:

Element nodes are type 1. If the sibling node is not an element node, it moves to the next nodes until an element node is found. This way, the result will be the same in both Internet Explorer and Firefox.

Get the First Child Element

The following code displays the first element node of the first <book>:

<script type="text/javascript" src="loadxmldoc.js">
<script type="text/javascript">
//check if the first node is an element node
function get_firstChild(n)
while (y.nodeType!=1)
return y;

<script type="text/javascript">




Example explained:

  1. Load "books.xml" into xmlDoc using loadXMLDoc()
  2. Use the get_firstChild fucntion on the first <book> element node to get the first child node that is an element node
  3. Output the node name of first child node that is an element node

Try it yourself


The following examples use a similar function: 

firstChild: Try it yourself  lastChild: Try it yourself

nextSibling: Try it yourself  previousSibling: Try it yourself

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