Added in API level 1

Summary: Inherited Constants | Methods | Inherited Methods

Attr

public interface Attr
implements Node

org.w3c.dom.Attr

The Attr interface represents an attribute in an Element object. Typically the allowable values for the attribute are defined in a schema associated with the document.

Attr objects inherit the Node interface, but since they are not actually child nodes of the element they describe, the DOM does not consider them part of the document tree. Thus, the Node attributes parentNode, previousSibling, and nextSibling have a null value for Attr objects. The DOM takes the view that attributes are properties of elements rather than having a separate identity from the elements they are associated with; this should make it more efficient to implement such features as default attributes associated with all elements of a given type. Furthermore, Attr nodes may not be immediate children of a DocumentFragment. However, they can be associated with Element nodes contained within a DocumentFragment. In short, users and implementors of the DOM need to be aware that Attr nodes have some things in common with other objects inheriting the Node interface, but they also are quite distinct.

The attribute's effective value is determined as follows: if this attribute has been explicitly assigned any value, that value is the attribute's effective value; otherwise, if there is a declaration for this attribute, and that declaration includes a default value, then that default value is the attribute's effective value; otherwise, the attribute does not exist on this element in the structure model until it has been explicitly added. Note that the Node.nodeValue attribute on the Attr instance can also be used to retrieve the string version of the attribute's value(s).

If the attribute was not explicitly given a value in the instance document but has a default value provided by the schema associated with the document, an attribute node will be created with specified set to false. Removing attribute nodes for which a default value is defined in the schema generates a new attribute node with the default value and specified set to false. If validation occurred while invoking Document.normalizeDocument(), attribute nodes with specified equals to false are recomputed according to the default attribute values provided by the schema. If no default value is associate with this attribute in the schema, the attribute node is discarded.

In XML, where the value of an attribute can contain entity references, the child nodes of the Attr node may be either Text or EntityReference nodes (when these are in use; see the description of EntityReference for discussion).

The DOM Core represents all attribute values as simple strings, even if the DTD or schema associated with the document declares them of some specific type such as tokenized.

The way attribute value normalization is performed by the DOM implementation depends on how much the implementation knows about the schema in use. Typically, the value and nodeValue attributes of an Attr node initially returns the normalized value given by the parser. It is also the case after Document.normalizeDocument() is called (assuming the right options have been set). But this may not be the case after mutation, independently of whether the mutation is performed by setting the string value directly or by changing the Attr child nodes. In particular, this is true when character references are involved, given that they are not represented in the DOM and they impact attribute value normalization. On the other hand, if the implementation knows about the schema in use when the attribute value is changed, and it is of a different type than CDATA, it may normalize it again at that time. This is especially true of specialized DOM implementations, such as SVG DOM implementations, which store attribute values in an internal form different from a string.

The following table gives some examples of the relations between the attribute value in the original document (parsed attribute), the value as exposed in the DOM, and the serialization of the value:

Examples	Parsed attribute value	Initial `Attr.value`	Serialized attribute value
Character reference	"x²=5"	"x²=5"	"x²=5"
Built-in character entity	"y<6"	"y<6"	"y<6"
Literal newline between	"x=5 y=6"	"x=5 y=6"	"x=5 y=6"
Normalized newline between	"x=5 y=6"	"x=5 y=6"	"x=5 y=6"
Entity `e` with literal newline	<!ENTITY e '... ...'> [...]> "x=5&e;y=6"	Dependent on Implementation and Load Options	Dependent on Implementation and Load/Save Options

Summary

Inherited constants

From interface org.w3c.dom.Node

`short`	`ATTRIBUTE_NODE` The node is an `Attr`.
`short`	`CDATA_SECTION_NODE` The node is a `CDATASection`.
`short`	`COMMENT_NODE` The node is a `Comment`.
`short`	`DOCUMENT_FRAGMENT_NODE` The node is a `DocumentFragment`.
`short`	`DOCUMENT_NODE` The node is a `Document`.
`short`	`DOCUMENT_POSITION_CONTAINED_BY` The node is contained by the reference node.
`short`	`DOCUMENT_POSITION_CONTAINS` The node contains the reference node.
`short`	`DOCUMENT_POSITION_DISCONNECTED` The two nodes are disconnected.
`short`	`DOCUMENT_POSITION_FOLLOWING` The node follows the reference node.
`short`	`DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC` The determination of preceding versus following is implementation-specific.
`short`	`DOCUMENT_POSITION_PRECEDING` The second node precedes the reference node.
`short`	`DOCUMENT_TYPE_NODE` The node is a `DocumentType`.
`short`	`ELEMENT_NODE` The node is an `Element`.
`short`	`ENTITY_NODE` The node is an `Entity`.
`short`	`ENTITY_REFERENCE_NODE` The node is an `EntityReference`.
`short`	`NOTATION_NODE` The node is a `Notation`.
`short`	`PROCESSING_INSTRUCTION_NODE` The node is a `ProcessingInstruction`.
`short`	`TEXT_NODE` The node is a `Text` node.

Public methods
`abstract String`	`getName()` Returns the name of this attribute.
`abstract Element`	`getOwnerElement()` The `Element` node this attribute is attached to or `null` if this attribute is not in use.
`abstract TypeInfo`	`getSchemaTypeInfo()` The type information associated with this attribute.
`abstract boolean`	`getSpecified()` `True` if this attribute was explicitly given a value in the instance document, `false` otherwise.
`abstract String`	`getValue()` On retrieval, the value of the attribute is returned as a string.
`abstract boolean`	`isId()` Returns whether this attribute is known to be of type ID (i.e.
`abstract void`	`setValue(String value)` On retrieval, the value of the attribute is returned as a string.

Inherited methods

From interface


        
          org.w3c.dom.Node

`abstract Node`	`appendChild(Node newChild)` Adds the node `newChild` to the end of the list of children of this node.
`abstract Node`	`cloneNode(boolean deep)` Returns a duplicate of this node, i.e., serves as a generic copy constructor for nodes.
`abstract short`	`compareDocumentPosition(Node other)` Compares the reference node, i.e.
`abstract NamedNodeMap`	`getAttributes()` A `NamedNodeMap` containing the attributes of this node (if it is an `Element`) or `null` otherwise.
`abstract String`	`getBaseURI()` The absolute base URI of this node or `null` if the implementation wasn't able to obtain an absolute URI.
`abstract NodeList`	`getChildNodes()` A `NodeList` that contains all children of this node.
`abstract Object`	`getFeature(String feature, String version)` This method returns a specialized object which implements the specialized APIs of the specified feature and version, as specified in .
`abstract Node`	`getFirstChild()` The first child of this node.
`abstract Node`	`getLastChild()` The last child of this node.
`abstract String`	`getLocalName()` Returns the local part of the qualified name of this node.
`abstract String`	`getNamespaceURI()` The namespace URI of this node, or `null` if it is unspecified (see ).
`abstract Node`	`getNextSibling()` The node immediately following this node.
`abstract String`	`getNodeName()` The name of this node, depending on its type; see the table above.
`abstract short`	`getNodeType()` A code representing the type of the underlying object, as defined above.
`abstract String`	`getNodeValue()` The value of this node, depending on its type; see the table above.
`abstract Document`	`getOwnerDocument()` The `Document` object associated with this node.
`abstract Node`	`getParentNode()` The parent of this node.
`abstract String`	`getPrefix()` The namespace prefix of this node, or `null` if it is unspecified.
`abstract Node`	`getPreviousSibling()` The node immediately preceding this node.
`abstract String`	`getTextContent()` This attribute returns the text content of this node and its descendants.
`abstract Object`	`getUserData(String key)` Retrieves the object associated to a key on a this node.
`abstract boolean`	`hasAttributes()` Returns whether this node (if it is an element) has any attributes.
`abstract boolean`	`hasChildNodes()` Returns whether this node has any children.
`abstract Node`	`insertBefore(Node newChild, Node refChild)` Inserts the node `newChild` before the existing child node `refChild`.
`abstract boolean`	`isDefaultNamespace(String namespaceURI)` This method checks if the specified `namespaceURI` is the default namespace or not.
`abstract boolean`	`isEqualNode(Node arg)` Tests whether two nodes are equal.
`abstract boolean`	`isSameNode(Node other)` Returns whether this node is the same node as the given one.
`abstract boolean`	`isSupported(String feature, String version)` Tests whether the DOM implementation implements a specific feature and that feature is supported by this node, as specified in .
`abstract String`	`lookupNamespaceURI(String prefix)` Look up the namespace URI associated to the given prefix, starting from this node.
`abstract String`	`lookupPrefix(String namespaceURI)` Look up the prefix associated to the given namespace URI, starting from this node.
`abstract void`	`normalize()` Puts all `Text` nodes in the full depth of the sub-tree underneath this `Node`, including attribute nodes, into a "normal" form where only structure (e.g., elements, comments, processing instructions, CDATA sections, and entity references) separates `Text` nodes, i.e., there are neither adjacent `Text` nodes nor empty `Text` nodes.
`abstract Node`	`removeChild(Node oldChild)` Removes the child node indicated by `oldChild` from the list of children, and returns it.
`abstract Node`	`replaceChild(Node newChild, Node oldChild)` Replaces the child node `oldChild` with `newChild` in the list of children, and returns the `oldChild` node.
`abstract void`	`setNodeValue(String nodeValue)` The value of this node, depending on its type; see the table above.
`abstract void`	`setPrefix(String prefix)` The namespace prefix of this node, or `null` if it is unspecified.
`abstract void`	`setTextContent(String textContent)` This attribute returns the text content of this node and its descendants.
`abstract Object`	`setUserData(String key, Object data, UserDataHandler handler)` Associate an object to a key on this node.

Public methods

getName

Added in API level 1

public abstract String getName ()

Returns the name of this attribute. If Node.localName is different from null, this attribute is a qualified name.

Returns
`String`

getOwnerElement

Added in API level 1

public abstract Element getOwnerElement ()

The Element node this attribute is attached to or null if this attribute is not in use.

Returns
`Element`

getSchemaTypeInfo

Added in API level 8

public abstract TypeInfo getSchemaTypeInfo ()

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

Returns
`TypeInfo`

getSpecified

Added in API level 1

public abstract boolean getSpecified ()

True if this attribute was explicitly given a value in the instance document, false otherwise. If the application changed the value of this attribute node (even if it ends up having the same value as the default value) then it is set to true. The implementation may handle attributes with default values from other schemas similarly but applications should use Document.normalizeDocument() to guarantee this information is up-to-date.

Returns
`boolean`

getValue

Added in API level 1

public abstract String getValue ()

On retrieval, the value of the attribute is returned as a string. Character and general entity references are replaced with their values. See also the method getAttribute on the Element interface.
On setting, this creates a Text node with the unparsed contents of the string, i.e. any characters that an XML processor would recognize as markup are instead treated as literal text. See also the method Element.setAttribute().
Some specialized implementations, such as some [SVG 1.1] implementations, may do normalization automatically, even after mutation; in such case, the value on retrieval may differ from the value on setting.

Returns
`String`

isId

Added in API level 8

public abstract boolean isId ()

Returns whether this attribute is known to be of type ID (i.e. to contain an identifier for its owner element) or not. When it is and its value is unique, the ownerElement of this attribute can be retrieved using the method Document.getElementById . The implementation could use several ways to determine if an attribute node is known to contain an identifier:

If validation occurred using an XML Schema [XML Schema Part 1] while loading the document or while invoking Document.normalizeDocument(), the post-schema-validation infoset contributions (PSVI contributions) values are used to determine if this attribute is a schema-determined ID attribute using the schema-determined ID definition in [XPointer] .
If validation occurred using a DTD while loading the document or while invoking Document.normalizeDocument(), the infoset [type definition] value is used to determine if this attribute is a DTD-determined ID attribute using the DTD-determined ID definition in [XPointer] .
from the use of the methods Element.setIdAttribute(), Element.setIdAttributeNS(), or Element.setIdAttributeNode(), i.e. it is an user-determined ID attribute;
Note: XPointer framework (see section 3.2 in [XPointer] ) consider the DOM user-determined ID attribute as being part of the XPointer externally-determined ID definition.
using mechanisms that are outside the scope of this specification, it is then an externally-determined ID attribute. This includes using schema languages different from XML schema and DTD.

If validation occurred while invoking Document.normalizeDocument(), all user-determined ID attributes are reset and all attribute nodes ID information are then reevaluated in accordance to the schema used. As a consequence, if the Attr.schemaTypeInfo attribute contains an ID type, isId will always return true.

Returns
`boolean`

setValue

Added in API level 1

public abstract void setValue (String value)

Parameters
`value`	`String`

Throws
`DOMException`	NO_MODIFICATION_ALLOWED_ERR: Raised when the node is readonly.