Node

A Node is an interface from which a number of DOM types inherit, and allows these various types to be treated (or tested) similarly.

The following interfaces all inherit from Node its methods and properties: Document, Element, CharacterData (which Text, Comment, and CDATASection inherit), ProcessingInstruction, DocumentFragment, DocumentType, Notation, Entity, EntityReference

These interfaces may return null in particular cases where the methods and properties are not relevant. They may throw an exception - for example when adding children to a node type for which no children can exist.

Properties

Inherits properties from its parents EventTarget.^[1]

Node.baseURI Read only

Returns a DOMString representing the base URL. The concept of base URL changes from one language to another; in HTML, it corresponds to the protocol, the domain name and the directory structure, that is all until the last '/'.

Node.baseURIObject

(Not available to web content.) The read-only nsIURI object representing the base URI for the element.

Node.childNodes Read only

Returns a live NodeList containing all the children of this node. NodeList being live means that if the children of the Node change, the NodeList object is automatically updated.

Node.firstChild Read only

Returns a Node representing the first direct child node of the node, or null if the node has no child.

Node.lastChild Read only

Returns a Node representing the last direct child node of the node, or null if the node has no child.

Node.localName Read only

Returns a DOMString representing the local part of the qualified name of an element. In Firefox 3.5 and earlier, the property upper-cases the local name for HTML elements (but not XHTML elements). In later versions, this does not happen, so the property is in lower case for both HTML and XHTML.
Though recent specifications require localName to be defined on the Element interface, Gecko-based browsers still implement it on the Node interface.

Node.namespaceURI Read only

The namespace URI of this node, or null if it is no namespace. In Firefox 3.5 and earlier, HTML elements are in no namespace. In later versions, HTML elements are in the http://www.w3.org/1999/xhtml namespace in both HTML and XML trees.
Though recent specifications require namespaceURI to be defined on the Element interface, Gecko-based browsers still implement it on the Node interface.

Node.nextSibling Read only

Returns a Node representing the next node in the tree, or null if there isn't such node.

Node.nodeName Read only

Returns a DOMString containing the name of the Node. The structure of the name will differ with the name type. E.g. An HTMLElement will contain the name of the corresponding tag, like 'audio' for an HTMLAudioElement, a Text node will have the '#text' string, or a Document node will have the '#document' string.

Node.nodePrincipal

A nsIPrincipal representing the node principal.

Node.nodeTypeRead only

Returns an unsigned short representing the type of the node. Possible values are:

Name	Value
ELEMENT_NODE	1
ATTRIBUTE_NODE	2
TEXT_NODE	3
CDATA_SECTION_NODE	4
ENTITY_REFERENCE_NODE	5
ENTITY_NODE	6
PROCESSING_INSTRUCTION_NODE	7
COMMENT_NODE	8
DOCUMENT_NODE	9
DOCUMENT_TYPE_NODE	10
DOCUMENT_FRAGMENT_NODE	11
NOTATION_NODE	12

Node.nodeValue

Is a DOMString representing the value of an object. For most Node types, this returns null and any set operation is ignored. For nodes of type TEXT_NODE (Text objects), COMMENT_NODE (Comment objects), and PROCESSING_INSTRUCTION_NODE (ProcessingInstruction objects), the value corresponds to the text data contained in the object.

Node.ownerDocument Read only

Returns the Document that this node belongs to. If no document is associated with it, returns null.

Node.parentNode Read only

Returns a Node that is the parent of this node. If there is no such node, like if this node is the top of the tree or if doesn't participate in a tree, this property returns null.

Node.parentElement Read only

Returns an Element that is the parent of this node. If the node has no parent, or if that parent is not an Element, this property returns null.

Node.prefix Read only

Is a DOMString representing the namespace prefix of the node, or null if no prefix is specified.
Though recent specifications require prefix to be defined on the Element interface, Gecko-based browsers still implement it on the Node interface.

Node.previousSibling Read only

Returns a Node representing the previous node in the tree, or null if there isn't such node.

Node.rootNode Read only

Returns a Node object representing the topmost node in the tree, or the current node if it's the topmost node in the tree. This is found by walking backward along Node.parentNode until the top is reached.

Node.textContent

Is a DOMString representing the textual content of an element and all its descendants.

Methods

Inherits methods from its parent, EventTarget.^[1]

Node.appendChild()

Insert a Node as the last child node of this element.

Node.cloneNode()

Clone a Node, and optionally, all of its contents. By default, it clones the content of the node.

Node.compareDocumentPosition()

Node.contains()

Node.getFeature()

Node.getUserData()

Allows a user to get some DOMUserData from the node.

Node.hasAttributes()

Returns a Boolean indicating if the element has any attributes, or not.

Node.hasChildNodes()

Returns a Boolean indicating if the element has any child nodes, or not.

Node.insertBefore()

Inserts the first Node given in a parameter immediately before the second, child of this element, Node.

Node.isDefaultNamespace()

Node.isEqualNode()

Returns a Boolean which indicates whether or not two nodes are of the same type and all their defining data points match.

Node.isSameNode()

Returns a Boolean value indicating whether or not the two nodes are the same (that is, they reference the same object).

Node.isSupported()

Returns a Boolean flag containing the result of a test whether the DOM implementation implements a specific feature and this feature is supported by the specific node.

Node.lookupPrefix()

Node.lookupNamespaceURI()

Node.normalize()

Clean up all the text nodes under this element (merge adjacent, remove empty).

Node.removeChild()

Removes a child node from the current element, which must be a child of the current node.

Node.replaceChild()

Replaces one child Node of the current one with the second one given in parameter.

Node.setUserData()

Allows a user to attach, or remove, DOMUserData to the node.

Examples

Browse all child nodes

The following function recursively cycles all child nodes of a node and executes a callback function upon them (and upon the parent node itself).

function DOMComb (oParent, oCallback) {
  if (oParent.hasChildNodes()) {
    for (var oNode = oParent.firstChild; oNode; oNode = oNode.nextSibling) {
      DOMComb(oNode, oCallback);
    }
  }
  oCallback.call(oParent);
}

Syntax

DOMComb(parentNode, callbackFunction);

Description

Recursively cycle all child nodes of parentNode and parentNode itself and execute the callbackFunction upon them as this objects.

Parameters

parentNode

The parent node (Node Object).

callbackFunction

The callback function (Function).

Sample usage

The following example send to the console.log the text content of the body:

function printContent () {
  if (this.nodeValue) { console.log(this.nodeValue); }
}

onload = function () {
  DOMComb(document.body, printContent);
};

Remove all children nested within a node

Element.prototype.removeAll = function () {
  while (this.firstChild) { this.removeChild(this.firstChild); }
  return this;
};

Sample usage

/* ... an alternative to document.body.innerHTML = "" ... */
document.body.removeAll();

Specifications

Browser compatibility

[1] WebKit and old versions of Blink incorrectly do not make Node inherit from EventTarget.

[2] In Gecko 22.0 (Firefox 22.0 / Thunderbird 22.0 / SeaMonkey 2.19) the attributes property was moved to Element.