Availability

DOM Level 1 Core

Subinterfaces

Attr, CharacterData, Document, DocumentFragment, DocumentType, Element, Entity, EntityReference, Notation, ProcessingInstruction

Also Implements

EventTarget

If the DOM implementation supports the Events module, every node in the document tree also implements the EventTarget interface and may have event listeners registered on it. The methods defined by the EventTarget interface are not included here; see the "EventTarget" and EventListener reference pages for details.

Constants

All Node objects implement one of the subinterfaces listed above. Every Node object has a nodeType property that specifies which of the subinterfaces it implements. These constants are the legal values for that property; their names are self-explanatory. Note that these are static properties of the Node( ) constructor function; they are not properties of individual Node objects. Also note that they are not supported by Internet Explorer 4, 5, or 6.

Node.ELEMENT_NODE = 1;                 // Element
Node.ATTRIBUTE_NODE = 2;               // Attr
Node.TEXT_NODE = 3;                    // Text
Node.CDATA_SECTION_NODE = 4;           // CDATASection
Node.ENTITY_REFERENCE_NODE = 5;        // EntityReference
Node.ENTITY_NODE = 6;                  // Entity
Node.PROCESSING_INSTRUCTION_NODE = 7;  // ProcessingInstruction
Node.COMMENT_NODE = 8;                 // Comment
Node.DOCUMENT_NODE = 9;                // Document
Node.DOCUMENT_TYPE_NODE = 10;          // DocumentType
Node.DOCUMENT_FRAGMENT_NODE = 11;      // DocumentFragment
Node.NOTATION_NODE = 12;               // Notation

Properties

readonly NamedNodeMap attributes

If this node is an element, specifies the attributes of that element. attributes is a NamedNodeMap object that allows attributes to be queried by name or by number and returns them in the form of Attr objects. In practice, it is almost always easier to use the getAttribute( ) method of the Element interface to obtain an attribute value as a string. Note that the returned NamedNodeMap object is "live": any changes to the attributes of this element are immediately visible through it.

readonly Node[] childNodes

Contains the child nodes of the current node. This property should never be null: for nodes with no children, childNodes is an array with length zero. This property is technically a NodeList object, but it behaves just like an array of Node objects. Note that the returned NodeList object is "live": any changes to this element's list of children are immediately visible through the NodeList.

readonly Node firstChild

The first child of this node, or null if the node has no children.

readonly Node lastChild

The last child of this node, or null if the node has no children.

readonly String localName [DOM Level 2]

In XML documents that use namespaces, specifies the local part of the element or attribute name. This property is never used with HTML documents. See also the namespaceURI and prefix properties.

readonly String namespaceURI [DOM Level 2]

In XML documents that use namespaces, specifies the URI of the namespace of an Element or Attribute node. This property is never used with HTML documents. See also the localName and prefix properties.

readonly Node nextSibling

The sibling node that immediately follows this one in the childNodes[] array of the parentNode, or null if there is no such node.

readonly String nodeName

The name of the node. For Element nodes, specifies the tag name of the element, which can also be retrieved with the tagName property of the Element interface. For other types of nodes, the value depends on the node type. See the upcoming table in the Section section for details.

readonly unsigned short nodeType

The type of the node; i.e., which subinterface the node implements. The legal values are defined by the previously listed constants. Since those constants are not supported by Internet Explorer, however, you may prefer to use hardcoded values instead of the constants. In HTML documents, the common values for this property are 1 for Element nodes, 3 for Text nodes, 8 for Comment nodes, and 9 for the single top-level Document node.

String nodeValue

The value of a node. For Text nodes, holds the text content. For other node types, the value depends on the nodeType, as shown in the upcoming table.

readonly Document ownerDocument

The Document object of which this node is a part. For Document nodes, this property is null.

readonly Node parentNode

The parent node (or container node) of this node, or null if there is no parent. Note that Document and Attr nodes never have parent nodes. Also, nodes that have been removed from the document or are newly created and have not yet been inserted into the document tree have a parentNode of null.

String prefix [DOM Level 2]

For XML documents that use namespaces, specifies the namespace prefix of an Element or Attribute node. This property is never used with HTML documents. See also the localName and namespaceURL properties. Setting this property can cause an exception if the new value contains illegal characters, is malformed, or does not match the namespaceURI property.

readonly Node previousSibling

The sibling node that immediately precedes this one in the childNodes[] array of the parentNode, or null if there is no such node.

Methods

appendChild( )

Adds a node to the document tree by appending it to the childNodes[] array of this node. If the node is already in the document tree, it is removed and then reinserted at its new position.

cloneNode( )

Makes a copy of this node, or of the node and all its descendants.

hasAttributes( ) [DOM Level 2]

Returns true if this node is an Element and has any attributes.

hasChildNodes( )

Returns true if this node has any children.

insertBefore( )

Inserts a node into the document tree immediately before the specified child of this node. If the node being inserted is already in the tree, it is removed and reinserted at its new location.

isSupported( ) [DOM Level 2]

Returns true if the specified version number of a named feature is supported by this node.

normalize( )

"Normalizes" all Text node descendants of this node by deleting empty Text nodes and merging adjacent Text nodes.

removeChild( )

Removes (and returns) the specified child node from the document tree.

replaceChild( )

Removes (and returns) the specified child node from the document tree, replacing it with another node.

Description

All objects in a document tree (including the Document object itself ) implement the Node interface, which provides the fundamental properties and methods for traversing and manipulating the tree. The parentNode property and childNodes[] array allow you to move up and down the document tree. You can enumerate the children of a given node by looping through the elements of childNodes[] or by using the firstChild and nextSibling properties (or the lastChild and previousSibling properties, to loop backward). The appendChild( ), insertBefore( ), removeChild( ), and replaceChild( ) methods allow you to modify the document tree by altering the children of a node.

Every object in a document tree implements both the Node interface and a more specialized interface, such as Element or Text. The nodeType property specifies which subinterface a node implements. You can use this property to test the type of a node before using properties or methods of the more specialized interface. For example:

var n;   // Holds the node we're working with
if (n.nodeType == 1) {        // Or compare to the constant Node.ELEMENT_NODE
    var tagname = n.tagName;  // If the node is an Element, this is the tag name
} 

The nodeName and nodeValue properties specify additional information about a node, but their value depends on nodeType, as shown in the following table. Note that subinterfaces typically define specialized properties (such as the tagName property of Element nodes and the data property of Text nodes) for obtaining this information.

nodeType	nodeName	nodeValue
ELEMENT_NODE	The element's tag name	null
ATTRIBUTE_NODE	The attribute name	The attribute value
TEXT_NODE	#text	The text of the node
CDATA_SECTION_NODE	#cdata-section	The text of the node
ENTITY_REFERENCE_NODE	The name of the referenced entity	null
ENTITY_NODE	The entity name	null
PROCESSING_INSTRUCTION_NODE	The target of the PI	The remainder of the PI
COMMENT_NODE	#comment	The text of the comment
DOCUMENT_NODE	#document	null
DOCUMENT_TYPE_NODE	The document type name	null
DOCUMENT_FRAGMENT_NODE	#document-fragment	null
NOTATION_NODE	The notation name	null

See Also

Document, Element, Text; Chapter 17