DOM Element

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Table of contents

1. Properties
2. Methods
3. Event Handlers
4. Other Events
5. Constants

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« Gecko DOM Reference
This chapter provides a brief reference for the general methods, properties, and events available to most HTML and XML elements in the Gecko DOM.
Various W3C specifications apply to elements:

• DOM Core Specification—describes the core interfaces shared by most DOM objects in HTML and XML documents
• DOM HTML Specification—describes interfaces for objects in HTML and XHTML documents that build on the core specification
• DOM Events Specification—describes events shared by most DOM objects, building on the DOM Core and Views specifications
• Element Traversal Specification—describes the new attributes that allow traversal of elements in the DOM tree New in Firefox 3.5

The articles listed here span the above and include links to the appropriate W3C DOM specification.
While these interfaces are generally shared by most HTML and XML elements, there are more specialized interfaces for particular objects listed in the DOM HTML Specification. Note, however, that these HTML interfaces are "only for [HTML 4.01] and [XHTML 1.0] documents and are not guaranteed to work with any future version of XHTML." The HTML 5 draft does state it aims for backwards compatibility with these HTML interfaces but says of them that "some features that were formerly deprecated, poorly supported, rarely used or considered unnecessary have been removed." One can avoid the potential conflict by moving entirely to DOM XML attribute methods such as getAttribute().
Html, Head, Link, Title, Meta, Base, IsIndex, Style, Body, Form, Select, OptGroup, Option, Input, TextArea, Button, Label, FieldSet, Legend, UList, OList, DList, Directory, Menu, LI, Div, Paragraph, Heading, Quote, Pre, BR, BaseFont, Font, HR, Mod, Anchor, Image, Object, Param, Applet, Map, Area, Script, Table, TableCaption, TableCol, TableSection, TableRow, TableCell, FrameSet, Frame, IFrame

Properties

Name	Description	Type	Availability
attributes	All attributes associated with an element.	NamedNodeMap	All
baseURI	Base URI as a string	String	HTML, XUL
baseURIObject New in Firefox 3	The read-only nsIURI object representing the base URI for the element.	nsIURI	All (with UniversalXPConnect privileges)
childElementCount New in Firefox 3.5	The number of child nodes that are elements.	Number	HTML, XUL
childNodes	All child nodes of an element.	NodeList	All
children Requires Gecko 1.9	A live nsIDOMNodeList of the current child elements.	NodeList	HTML, XUL
classList Requires Gecko 1.9.2	Token list of class attribute	DOMTokenList	HTML
className	Gets/sets the class of the element.	String	HTML, XUL
clientHeight	The inner height of an element.	Number	HTML
clientLeft	The width of the left border of an element.	Number	HTML
clientTop	The width of the top border of an element.	Number	HTML
clientWidth	The inner width of an element.	Number	HTML
contentEditable Requires Gecko 1.9	Gets/sets whether or not the element is editable.	String	HTML, XUL
dir	Gets/sets the directionality of the element.	String	HTML, XUL
firstChild	The first direct child node of an element, or null if this element has no child nodes.	Node	All
firstElementChild Requires Gecko 1.9	The first direct child element of an element, or null if the element has no child elements.	Element	HTML, XUL
id	Gets/sets the id of the element.	String	HTML, XUL
innerHTML	Gets/sets the markup and content of the element.	String	HTML
isContentEditable Requires Gecko 2	Indicates whether or not the content of the element can be edited. Read only.	Boolean	HTML, XUL
lang	Gets/sets the language of an element's attributes, text, and element contents.	String	HTML
lastChild	The last direct child node of an element, or null if this element has no child nodes.	Node	All
lastElementChild Requires Gecko 1.9	The last direct child element of an element, or null if the element has no child elements.	Element	HTML, XUL
localName	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. Requires Gecko 1.9.2	String	All
Name	Description	Type	Availability
name	Gets/sets the name attribute of an element.	String	HTML
namespaceURI	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. Requires Gecko 1.9.2	String	All
nextSibling	The node immediately following the given one in the tree, or null if there is no sibling node.	Node	All
nextElementSibling New in Firefox 3.5	The element immediately following the given one in the tree, or null if there's no sibling node.	Element	HTML, XUL
nodeName	The name of the node.	String	All
nodePrincipal New in Firefox 3	The node's principal.	nsIPrincipal	All (with UniversalXPConnect privileges)
nodeType	A number representing the type of the node. Is always equal to 1 for DOM elements.	Number	All
nodeValue	The value of the node. Is always equal to null for DOM elements.	String	All
offsetHeight	The height of an element, relative to the layout.	Number	HTML
offsetLeft	The distance from this element's left border to its offsetParent's left border.	Number	HTML
offsetParent	The element from which all offset calculations are currently computed.	Element	HTML
offsetTop	The distance from this element's top border to its offsetParent's top border.	Number	HTML
offsetWidth	The width of an element, relative to the layout.	Number	HTML
ownerDocument	The document that this node is in, or null if the node is not inside of one.	Document	All
Name	Description	Type	Availability
parentNode	The parent element of this node, or null if the node is not inside of a DOM Document.	Node	All
prefix	The namespace prefix of the node, or null if no prefix is specified.	String	All
previousSibling	The node immediately preceding the given one in the tree, or null if there is no sibling node.	Node	All
previousElementSibling New in Firefox 3.5	The element immediately preceding the given one in the tree, or null if there is no sibling element.	Element	HTML, XUL
schemaTypeInfo	Returns TypeInfo regarding schema information for the element (also available on Attr).	TypeInfo	Not supported
scrollHeight	The scroll view height of an element.	Number	HTML
scrollLeft	Gets/sets the left scroll offset of an element.	Number	HTML
scrollTop	Gets/sets the top scroll offset of an element.	Number	HTML
scrollWidth	The scroll view width of an element.	Number	HTML
spellcheck	Controls spell-checking (present on all HTML elements)	Boolean	HTML
style	An object representing the declarations of an element's style attributes.	CSSStyleDeclaration	HTML, XUL
tabIndex	Gets/sets the position of the element in the tabbing order.	Number	HTML
tagName	The name of the tag for the given element.	String	All
textContent	Gets/sets the textual contents of an element and all its descendants.	String	All
title	A string that appears in a popup box when mouse is over the element.	String	HTML

Methods

Name & Description	Return	Availability
addEventListener( type, listener, useCapture ) Register an event handler to a specific event type on the element.	-	All
appendChild( appendedNode ) Insert a node as the last child node of this element.	Node	All
blur() Removes keyboard focus from the current element.	-	HTML, XUL
click() Simulates a click on the current element.	-	HTML, XUL
cloneNode( deep ) Clone a node, and optionally, all of its contents.	Node	All
compareDocumentPosition ( otherNode )	Number	All
dispatchEvent( event ) Dispatch an event to this node in the DOM.	Boolean	All
focus() Gives keyboard focus to the current element.	-	HTML, XUL
getAttribute( name ) Retrieve the value of the named attribute from the current node.	Object	All
getAttributeNS( namespace, name ) Retrieve the value of the attribute with the specified name and namespace, from the current node.	Object	All
getAttributeNode( name ) Retrieve the node representation of the named attribute from the current node.	Attr	All
getAttributeNodeNS( namespace, name ) Retrieve the node representation of the attribute with the specified name and namespace, from the current node.	Attr	All
getBoundingClientRect ( )
getClientRects ( ) Returns a collection of rectangles that indicate the bounding rectangles for each line of text in a client.
Name & Description	Return	Availability
getElementsByClassName ( )	NodeList
getElementsByTagName( name ) Retrieve a set of all descendant elements, of a particular tag name, from the current element.	NodeList	All
getElementsByTagNameNS( namespace, name ) Retrieve a set of all descendant elements, of a particular tag name and namespace, from the current element.	NodeList	All
getFeature ( feature, version  )	Object	All
getUserData ( key )	DOMUserData	All
hasAttribute( name ) Check if the element has the specified attribute, or not.	Boolean	All
hasAttributeNS( namespace, name ) Check if the element has the specified attribute, in the specified namespace, or not.	Boolean	All
hasAttributes() Check if the element has any attributes, or not.	Boolean	All
hasChildNodes() Check if the element has any child nodes, or not.	Boolean	All
insertBefore( insertedNode, adjacentNode ) Inserts the first node before the second, child, Node in the DOM.	Node	All
isDefaultNamespace ( namespaceURI )	Boolean	All
isEqualNode ( nodeArg )	Boolean	All
isSameNode ( otherNode )	Boolean	All
isSupported ( feature, version )	Boolean	All
lookupNamespaceURI ( prefix )	String	All
lookupPrefix ( namespaceURI )	String	All
mozMatchesSelector( selector ) Returns whether or not the element would be selected by the specified selector string.	Boolean	All
normalize() Clean up all the text nodes under this element (merge adjacent, remove empty).	-	All
querySelector( selectors[, nsresolver] ) New in Firefox 3.5	Node	All
querySelectorAll( selectors[, nsresolver] ) New in Firefox 3.5	NodeList	All
removeAttribute( name ) Remove the named attribute from the current node.	-	All
removeAttributeNS( namespace, name ) Remove the attribute with the specified name and namespace, from the current node.	-	All
Name & Description	Return	Availability
removeAttributeNode( attrNode ) Remove the node representation of the named attribute from the current node.	-	All
removeChild( removedNode ) Removes a child node from the current element.	Node	All
removeEventListener( type, handler, useCapture ) Removes an event listener from the element.	-	All
replaceChild( insertedNode, replacedNode ) Replaces one child node in the current element with another.	Node	All
scrollIntoView( alignWithTop ) Scrolls the page until the element gets into the view.	-	HTML
setAttribute( name, value ) Set the value of the named attribute from the current node.	-	All
setAttributeNS( namespace, name, value ) Set the value of the attribute with the specified name and namespace, from the current node.	-	All
setAttributeNode( name, attrNode ) Set the node representation of the named attribute from the current node.	-	All
setAttributeNodeNS( namespace, name, attrNode ) Set the node representation of the attribute with the specified name and namespace, from the current node.	-	All
setCapture( retargetToElement ) Sets up mouse event capture, redirecting all mouse events to this element.	-	All
setIdAttribute (name, isIdBoolean) Sets the attribute to be treated as an ID type attribute.	-	Not supported
setIdAttributeNS ( namespaceURI, localName, isIdBoolean ) Sets the attribute to be treated as an ID type attribute.	-	Not supported
setIdAttributeNode ( idAttr, isIdBoolean ) Sets the attribute to be treated as an ID type attribute.	-	Not supported
setUserData ( key, data, handler )	DOMUserData	All

Event Handlers

These are properties that correspond to the HTML 'on' event attributes.
Unlike the corresponding attributes, the values of these properties are functions (or any other object implementing the EventListener interface) rather than a string. In fact, assigning an event attribute in HTML creates a wrapper function around the specified code. For example, given the following HTML:

click me!

If element is a reference to this div, the value of element.onclick is effectively:

function onclick(event) {
   foo();
}

Note how the event object is passed as parameter event to this wrapper function.

element.onafterscriptexecute Requires Gecko 2.0 Non-standard

The event handling code for the afterscriptexecute event; this is used only for