--- title: Attr slug: Web/API/Attr translation_of: Web/API/Attr ---

{{APIRef("DOM")}}

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., {{domxref("Element.getAttribute()")}}), but certain functions (e.g., {{domxref("Element.getAttributeNode()")}}) or means of iterating return Attr types.

{{InheritanceDiagram}}

Warning: Starting in Gecko 7.0 {{geckoRelease("7.0")}}, 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

{{domxref("Attr.name", "name")}} {{readOnlyInline}}
The attribute's name.
{{domxref("Attr.namespaceURI", "namespaceURI")}} {{readOnlyInline}}
A {{domxref("DOMString")}} representing the namespace URI of the attribute, or null if there is no namespace.
{{domxref("Attr.localName", "localName")}} {{readOnlyInline}}
A {{domxref("DOMString")}} representing the local part of the qualified name of the attribute.
{{domxref("Attr.prefix", "prefix")}} {{readOnlyInline}}
A {{domxref("DOMString")}} representing the namespace prefix of the attribute, or null if no prefix is specified.
{{domxref("Attr.ownerElement", "ownerElement")}} {{readOnlyInline}}

The element holding the attribute.

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

Gecko outputs a deprecation note starting from Gecko 7.0 {{geckoRelease("7.0")}}. This note was removed again in Gecko 49.0 {{geckoRelease("49.0")}}.

{{domxref("Attr.specified", "specified")}} {{readOnlyInline}}
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.
{{domxref("Attr.value", "value")}}
The attribute's value.

Note: DOM Level 3 defined namespaceURI, localName and prefix on the {{domxref("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_inline(14)}}
This property now always returns an empty {{domxref("NodeList")}}.
firstChild {{obsolete_inline(14)}}
This property now always returns NULL.
isId {{readOnlyInline}}
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 {{Glossary("DTD")}} or other schema description.
lastChild {{obsolete_inline(14)}}
This property now always returns NULL.
nextSibling
This property now always returns NULL.
nodeName
Use {{domxref("Attr.name")}} instead.
nodeType
This property now always returns 2 (ATTRIBUTE_NODE).
nodeValue
Use {{domxref("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 {{obsolete_inline}} {{readOnlyInline}}
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 {{domxref("Document.normalizeDocument")}}, this property may not be reliable if the node was moved.
specified
This property now always returns true.
textContent
Use {{domxref("Attr.value")}} instead.

The following methods have been deprecated:

appendChild() {{obsolete_inline(14)}}
Modify the value of {{domxref("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 {{domxref("Element.setAttribute()")}} instead.
createAttributeNS()
Use {{domxref("Element.setAttributeNS()")}} instead.
getAttributeNode()
Use {{domxref("Element.getAttribute()")}} instead.
getAttributeNodeNS()
Use {{domxref("Element.getAttributeNS()")}} instead.
hasAttributes() {{obsolete_inline("21.0")}}
This method now always returns false.
hasChildNodes()
This method now always returns false.
insertBefore()
Modify the value of {{domxref("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 {{domxref("Element.removeAttribute()")}} instead.
removeChild() {{obsolete_inline(14)}}
Modify the value of {{domxref("Attr.value")}} instead.
replaceChild() {{obsolete_inline(14)}}
Modify the value of {{domxref("Attr.value")}} instead.
setAttributeNode()
Use {{domxref("Element.setAttribute()")}} instead.
setAttributeNodeNS()
Use {{domxref("Element.setAttributeNS()")}} instead.

Specifications

Specification Status Comment
{{SpecName("DOM WHATWG", "#interface-attr", "Attr")}} {{Spec2("DOM WHATWG")}} Added ownerElement property back
{{SpecName("DOM4", "#interface-attr", "Attr")}} {{Spec2("DOM4")}} Moved namespaceURI, prefix and localName from {{domxref("Node")}} to this API and removed ownerElement, schemaTypeInfo and isId.
{{SpecName("DOM3 Core", "core.html#ID-637646024", "Attr")}} {{Spec2("DOM3 Core")}} Initial definition

Browser compatibility

{{Compat("api.Attr")}}