Node

Node is an interface from which a number of DOM API object types inherit; it allows these various types to be treated similarly, for example inheriting the same set of methods, or being tested in the same way.

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.

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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.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

Returns / Sets the value of the current node

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.previousSibling Read only

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

Node.textContent

Returns / Sets the textual content of an element and all its descendants.

Deprecated properties

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 has been replaced by Node.getRootNode().

Obsolete properties

Node.localName Read only

Returns a DOMString representing the local part of the qualified name of an element.

Note: 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.

Node.namespaceURI Read only

The namespace URI of this node, or null if it is no namespace.

Note: In Firefox 3.5 and earlier, HTML elements are in no namespace. In later versions, HTML elements are in the https://www.w3.org/1999/xhtml/ namespace in both HTML and XML trees.

Node.prefix Read only

Is a DOMString representing the namespace prefix of the node, or null if no prefix is specified.

Methods

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

Node.appendChild()

Adds the specified childNode argument as the last child to the current node.
If the argument referenced an existing node on the DOM tree, the node will be detached from its current position and attached at the new position.

Node.cloneNode()

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

Node.compareDocumentPosition()

Compares the position of the current node against another node in any other document.

Node.contains()

Returns a Boolean value indicating whether a node is a descendant of a given node or not.

Node.getRootNode()

Returns the context object's root which optionally includes the shadow root if it is available. 

Node.hasChildNodes()

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

Node.insertBefore()

Inserts a Node before the reference node as a child of the current node.

Node.isDefaultNamespace()

Accepts a namespace URI as an argument and returns a Boolean with a value of true if the namespace is the default namespace on the given node or false if not.

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.lookupPrefix()

Returns a DOMString containing the prefix for a given namespace URI, if present, and null if not. When multiple prefixes are possible, the result is implementation-dependent.

Node.lookupNamespaceURI()

Accepts a prefix and returns the namespace URI associated with it on the given node if found (and null if not). Supplying null for the prefix will return the default namespace.

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.

Obsolete methods

Node.getFeature()

x

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.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.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.

[3] The properties were moved to the Element and Attr APIs according to the DOM4 standard.