Attr
The Attr
interface represents one of an element's attributes as an object. In most situations, you will directly retrieve the attribute value as a string (e.g., Element.getAttribute()
), but some cases may require interacting with Attr
instances (e.g., Element.getAttributeNode()
).
The core idea of an object of type Attr
is the association between a name and a value. An attribute may also be part of a namespace and, in this case, it also has a URI identifying the namespace, and a prefix that is an abbreviation for the namespace.
The name is deemed local when it ignores the eventual namespace prefix and deemed qualified when it includes the prefix of the namespace, if any, separated from the local name by a colon (:
). We have three cases: an attribute outside of a namespace, an attribute inside a namespace without a prefix defined, an attribute inside a namespace with a prefix:
Attribute | Namespace name | Namespace prefix | Attribute local name | Attribute qualified name |
---|---|---|---|---|
myAttr |
none | none | myAttr |
myAttr |
myAttr |
mynamespace |
none | myAttr |
myAttr |
myAttr |
mynamespace |
myns |
myAttr |
myns:myAttr |
Note: This interface represents only attributes present in the tree representation of the Element
, being a SVG, an HTML or a MathML element. It doesn't represent the property of an interface associated with such element, such as HTMLTableElement
for a <table>
element. (See this article for more information about attributes and how they are reflected into properties.)
Instance properties
This interface also inherits the properties of its parent interfaces, Node
and EventTarget
.
localName
Read only-
A string representing the local part of the qualified name of the attribute.
name
Read only-
The attribute's qualified name. If the attribute is not in a namespace, it will be the same as
localName
property. namespaceURI
Read only-
A string representing the URI of the namespace of the attribute, or
null
if there is no namespace. ownerElement
Read only-
The
Element
the attribute belongs to. prefix
Read only-
A string representing the namespace prefix of the attribute, or
null
if a namespace without prefix or no namespace are specified. specified
Read only Deprecated-
This property always returns
true
. value
-
The attribute's value, a string that can be set and get using this property.
Instance methods
This interface has no specific methods, but inherits the methods of its parent interfaces, Node
and EventTarget
.
Specifications
Specification |
---|
DOM Standard # interface-attr |
Browser compatibility
BCD tables only load in the browser
See also
- Other nodes are
CDATASection
,CharacterData
,Comment
,Document
,Element
,ProcessingInstruction
, andText
.