Web/API/Attr

The Attr interface represents one of a DOM element's attributes as an object. In most DOM methods, you will directly retrieve the attribute as a string (e.g., Element.getAttribute()), but certain functions (e.g., Element.getAttributeNode()) or means of iterating return Attr types.

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Warning: Starting in Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4), a number of deprecated properties and methods output warning messages to the console. You should revise your code accordingly. See Deprecated properties and methods for a complete list.

Properties

name Read only

The attribute's name.

namespaceURI Read only

A DOMString representing the namespace URI of the attribute, or null if there is no namespace.

localName Read only

A DOMString representing the local part of the qualified name of the attribute.

prefix Read only

A DOMString representing the namespace prefix of the attribute, or null if no prefix is specified.

ownerElement Read only

The element holding the attribute.

Note: DOM Level 4 removed this property. The assumption was that since you get an Attr object from an Element, you should already know the associated element. As that doesn't hold true in cases like Attr objects being returned by Document.evaluate, the DOM Living Standard reintroduced the property.

Gecko outputs a deprecation note starting from Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4). This note was removed again in Gecko 49.0 (Firefox 49.0 / Thunderbird 49.0 / SeaMonkey 2.46).

specified Read only

This property always returns true. Originally, it returned true if the attribute was explicitly specified in the source code or by a script, and false if its value came from the default one defined in the document's DTD.

value

The attribute's value.

Note: DOM Level 3 defined namespaceURI, localName and prefix on the Node interface. In DOM4 they were moved to Attr.

This change is implemented in Chrome since version 46.0 and Firefox since version 48.0.

Deprecated properties and methods

The following properties have been deprecated. Where available, the appropriate replacement is noted.

attributes

This property now always returns NULL.

childNodes Obsolete since Gecko 14

This property now always returns an empty NodeList.

firstChild Obsolete since Gecko 14

This property now always returns NULL.

isId Read only

Indicates whether the attribute is an "ID attribute". An "ID attribute" being an attribute which value is expected to be unique across a DOM Document. In HTML DOM, "id" is the only ID attribute, but XML documents could define others. Whether or not an attribute is unique is often determined by a DTD or other schema description.

lastChild Obsolete since Gecko 14

This property now always returns NULL.

nextSibling

This property now always returns NULL.

nodeName

Use Attr.name instead.

nodeType

This property now always returns 2 (ATTRIBUTE_NODE).

nodeValue

Use Attr.value instead.

ownerDocument

You shouldn't have been using this in the first place, so you probably don't care that this is going away.

parentNode

This property now always returns NULL.

previousSibling

This property now always returns NULL.

schemaTypeInfo ' Read only

The type information associated with this attribute. While the type information contained in this attribute is guaranteed to be correct after loading the document or invoking Document.normalizeDocument, this property may not be reliable if the node was moved.

specified

This property now always returns true.

textContent

Use Attr.value instead.

The following methods have been deprecated:

appendChild() Obsolete since Gecko 14

Modify the value of Attr.value instead.

cloneNode()

You shouldn't have been using this in the first place, so you probably don't care that this is going away.

createAttribute()

Use Element.setAttribute() instead.

createAttributeNS()

Use Element.setAttributeNS() instead.

getAttributeNode()

Use Element.getAttribute() instead.

getAttributeNodeNS()

Use Element.getAttributeNS() instead.

hasAttributes() Obsolete since Gecko 21.0

This method now always returns false.

hasChildNodes()

This method now always returns false.

insertBefore()

Modify the value of Attr.value instead.

isSupported()

You shouldn't have been using this in the first place, so you probably don't care that this is going away.

isEqualNode()

You shouldn't have been using this in the first place, so you probably don't care that this is going away.

normalize()

You shouldn't have been using this in the first place, so you probably don't care that this is going away.

removeAttributeNode()

Use Element.removeAttribute() instead.

removeChild() Obsolete since Gecko 14

Modify the value of Attr.value instead.

replaceChild() Obsolete since Gecko 14

Modify the value of Attr.value instead.

setAttributeNode()

Use Element.setAttribute() instead.

setAttributeNodeNS()

Use Element.setAttributeNS() instead.

Specifications

Specification	Status	Comment
DOMThe definition of 'Attr' in that specification.	Living Standard	Added ownerElement property back
DOM4The definition of 'Attr' in that specification.	Obsolete	Moved namespaceURI, prefix and localName from Node to this API and removed ownerElement, schemaTypeInfo and isId.
Document Object Model (DOM) Level 3 Core SpecificationThe definition of 'Attr' in that specification.	Obsolete	Initial definition

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
Attr	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 8	Opera Full support 8	Safari Full support 1.3	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0
localName	Chrome Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Edge Full support ≤18	Firefox Full support 48 Notes' Full support 48 Notes' Notes' This API was previously available on the Node API.	IE No support No	Opera Full support 33 Notes' Full support 33 Notes' Notes' This API was previously available on the Node API.	Safari Full support 1.3	WebView Android Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Chrome Android Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Firefox Android Full support 48 Notes' Full support 48 Notes' Notes' This API was previously available on the Node API.	Opera Android Full support 33 Notes' Full support 33 Notes' Notes' This API was previously available on the Node API.	Safari iOS Full support 1	Samsung Internet Android Full support 5.0 Notes' Full support 5.0 Notes' Notes' This API was previously available on the Node API.
namespaceURI	Chrome Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Edge Full support ≤18	Firefox Full support 48 Notes' Full support 48 Notes' Notes' This API was previously available on the Node API.	IE No support No	Opera Full support 33 Notes' Full support 33 Notes' Notes' This API was previously available on the Node API.	Safari Full support 1.3	WebView Android Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Chrome Android Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Firefox Android Full support 48 Notes' Full support 48 Notes' Notes' This API was previously available on the Node API.	Opera Android Full support 33 Notes' Full support 33 Notes' Notes' This API was previously available on the Node API.	Safari iOS Full support 1	Samsung Internet Android Full support 5.0 Notes' Full support 5.0 Notes' Notes' This API was previously available on the Node API.
prefix	Chrome Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Edge Full support ≤18	Firefox Full support 48 Notes' Full support 48 Notes' Notes' This API was previously available on the Node API.	IE No support No	Opera Full support 33 Notes' Full support 33 Notes' Notes' This API was previously available on the Node API.	Safari Full support 1.3	WebView Android Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Chrome Android Full support 46 Notes' Full support 46 Notes' Notes' This API was previously available on the Node API.	Firefox Android Full support 48 Notes' Full support 48 Notes' Notes' This API was previously available on the Node API.	Opera Android Full support 33 Notes' Full support 33 Notes' Notes' This API was previously available on the Node API.	Safari iOS Full support 1	Samsung Internet Android Full support 5.0 Notes' Full support 5.0 Notes' Notes' This API was previously available on the Node API.

Legend

Full support  

Full support

No support  

No support

See implementation notes.'

See implementation notes.

Attr by Mozilla Contributors is licensed under CC-BY-SA 2.5.