Element

AI-generated Key Takeaways

• The Element interface represents an element within an HTML or XML document and provides methods for interacting with its attributes and child elements.

• setIdAttributeNS and setIdAttributeNode methods allow declaring or undeclaring an attribute as a user-determined ID attribute, impacting element identification.

• Both methods influence Attr.isId and Document.getElementById but do not alter existing schemas or type information.

• Common exceptions for these methods include NO_MODIFICATION_ALLOWED_ERR and NOT_FOUND_ERR, indicating read-only nodes or missing attributes.

public interface Element implements Node

The Element interface represents an element in an HTML or XML document. Elements may have attributes associated with them; since the Element interface inherits from Node, the generic Node interface attribute attributes may be used to retrieve the set of all attributes for an element. There are methods on the Element interface to retrieve either an Attr object by name or an attribute value by name. In XML, where an attribute value may contain entity references, an Attr object should be retrieved to examine the possibly fairly complex sub-tree representing the attribute value. On the other hand, in HTML, where all attributes have simple string values, methods to directly access an attribute value can safely be used as a convenience.

Note: In DOM Level 2, the method normalize is inherited from the Node interface where it was moved.

See also the Document Object Model (DOM) Level 3 Core Specification.

Inherited Constant Summary

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 Method Summary

abstract String	getAttribute(String name) Retrieves an attribute value by name.
abstract String	getAttributeNS(String namespaceURI, String localName) Retrieves an attribute value by local name and namespace URI.
abstract Attr	getAttributeNode(String name) Retrieves an attribute node by name.
abstract Attr	getAttributeNodeNS(String namespaceURI, String localName) Retrieves an Attr node by local name and namespace URI.
abstract NodeList	getElementsByTagName(String name) Returns a NodeList of all descendant Elements with a given tag name, in document order.
abstract NodeList	getElementsByTagNameNS(String namespaceURI, String localName) Returns a NodeList of all the descendant Elements with a given local name and namespace URI in document order.
abstract TypeInfo	getSchemaTypeInfo() The type information associated with this element.
abstract String	getTagName() The name of the element.
abstract boolean	hasAttribute(String name) Returns true when an attribute with a given name is specified on this element or has a default value, false otherwise.
abstract boolean	hasAttributeNS(String namespaceURI, String localName) Returns true when an attribute with a given local name and namespace URI is specified on this element or has a default value, false otherwise.
abstract void	removeAttribute(String name) Removes an attribute by name.
abstract void	removeAttributeNS(String namespaceURI, String localName) Removes an attribute by local name and namespace URI.
abstract Attr	removeAttributeNode(Attr oldAttr) Removes the specified attribute node.
abstract void	setAttribute(String name, String value) Adds a new attribute.
abstract void	setAttributeNS(String namespaceURI, String qualifiedName, String value) Adds a new attribute.
abstract Attr	setAttributeNode(Attr newAttr) Adds a new attribute node.
abstract Attr	setAttributeNodeNS(Attr newAttr) Adds a new attribute.
abstract void	setIdAttribute(String name, boolean isId) If the parameter isId is true, this method declares the specified attribute to be a user-determined ID attribute .
abstract void	setIdAttributeNS(String namespaceURI, String localName, boolean isId) If the parameter isId is true, this method declares the specified attribute to be a user-determined ID attribute .
abstract void	setIdAttributeNode(Attr idAttr, boolean isId) If the parameter isId is true, this method declares the specified attribute to be a user-determined ID attribute .

Inherited Method Summary

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

public abstract String getAttribute (String name)

Retrieves an attribute value by name.

Parameters

name	The name of the attribute to retrieve.

Returns

• The Attr value as a string, or the empty string if that attribute does not have a specified or default value.

public abstract String getAttributeNS (String namespaceURI, String localName)

Retrieves an attribute value by local name and namespace URI.
Per [XML Namespaces] , applications must use the value null as the namespaceURI parameter for methods if they wish to have no namespace.

Parameters

namespaceURI	The namespace URI of the attribute to retrieve.
localName	The local name of the attribute to retrieve.

Returns

• The Attr value as a string, or the empty string if that attribute does not have a specified or default value.

Throws

DOMException	NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

public abstract Attr getAttributeNode (String name)

Retrieves an attribute node by name.
To retrieve an attribute node by qualified name and namespace URI, use the getAttributeNodeNS method.

Parameters

name	The name (nodeName) of the attribute to retrieve.

Returns

• The Attr node with the specified name ( nodeName) or null if there is no such attribute.

public abstract Attr getAttributeNodeNS (String namespaceURI, String localName)

Retrieves an Attr node by local name and namespace URI.
Per [XML Namespaces] , applications must use the value null as the namespaceURI parameter for methods if they wish to have no namespace.

Parameters

namespaceURI	The namespace URI of the attribute to retrieve.
localName	The local name of the attribute to retrieve.

Returns

• The Attr node with the specified attribute local name and namespace URI or null if there is no such attribute.

Throws

DOMException	NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

public abstract NodeList getElementsByTagName (String name)

Returns a NodeList of all descendant Elements with a given tag name, in document order.

Parameters

name	The name of the tag to match on. The special value "*" matches all tags.

Returns

• A list of matching Element nodes.

public abstract NodeList getElementsByTagNameNS (String namespaceURI, String localName)

Returns a NodeList of all the descendant Elements with a given local name and namespace URI in document order.

Parameters

namespaceURI	The namespace URI of the elements to match on. The special value "*" matches all namespaces.
localName	The local name of the elements to match on. The special value "*" matches all local names.

Returns

• A new NodeList object containing all the matched Elements.

Throws

DOMException	NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

public abstract TypeInfo getSchemaTypeInfo ()

The type information associated with this element.

public abstract String getTagName ()

The name of the element. If Node.localName is different from null, this attribute is a qualified name. For example, in:

 <elementExample id="demo"> ...
 </elementExample> , 

tagName has the value "elementExample". Note that this is case-preserving in XML, as are all of the operations of the DOM. The HTML DOM returns the tagName of an HTML element in the canonical uppercase form, regardless of the case in the source HTML document.

public abstract boolean hasAttribute (String name)

Returns true when an attribute with a given name is specified on this element or has a default value, false otherwise.

Parameters

name	The name of the attribute to look for.

Returns

• true if an attribute with the given name is specified on this element or has a default value, false otherwise.

public abstract boolean hasAttributeNS (String namespaceURI, String localName)

Returns true when an attribute with a given local name and namespace URI is specified on this element or has a default value, false otherwise.
Per [XML Namespaces] , applications must use the value null as the namespaceURI parameter for methods if they wish to have no namespace.

Parameters

namespaceURI	The namespace URI of the attribute to look for.
localName	The local name of the attribute to look for.

Returns

• true if an attribute with the given local name and namespace URI is specified or has a default value on this element, false otherwise.

Throws

DOMException	NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

public abstract void removeAttribute (String name)

Removes an attribute by name. If a default value for the removed attribute is defined in the DTD, a new attribute immediately appears with the default value as well as the corresponding namespace URI, local name, and prefix when applicable. The implementation may handle default values from other schemas similarly but applications should use Document.normalizeDocument() to guarantee this information is up-to-date.
If no attribute with this name is found, this method has no effect.
To remove an attribute by local name and namespace URI, use the removeAttributeNS method.

Parameters

name	The name of the attribute to remove.

Throws

DOMException	NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

public abstract void removeAttributeNS (String namespaceURI, String localName)

Removes an attribute by local name and namespace URI. If a default value for the removed attribute is defined in the DTD, a new attribute immediately appears with the default value as well as the corresponding namespace URI, local name, and prefix when applicable. The implementation may handle default values from other schemas similarly but applications should use Document.normalizeDocument() to guarantee this information is up-to-date.
If no attribute with this local name and namespace URI is found, this method has no effect.
Per [XML Namespaces] , applications must use the value null as the namespaceURI parameter for methods if they wish to have no namespace.

Parameters

namespaceURI	The namespace URI of the attribute to remove.
localName	The local name of the attribute to remove.

Throws

DOMException	NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

public abstract Attr removeAttributeNode (Attr oldAttr)

Removes the specified attribute node. If a default value for the removed Attr node is defined in the DTD, a new node immediately appears with the default value as well as the corresponding namespace URI, local name, and prefix when applicable. The implementation may handle default values from other schemas similarly but applications should use Document.normalizeDocument() to guarantee this information is up-to-date.

Parameters

oldAttr	The Attr node to remove from the attribute list.

Returns

• The Attr node that was removed.

Throws

DOMException	NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. NOT_FOUND_ERR: Raised if oldAttr is not an attribute of the element.

public abstract void setAttribute (String name, String value)

Adds a new attribute. If an attribute with that name is already present in the element, its value is changed to be that of the value parameter. This value is a simple string; it is not parsed as it is being set. So any markup (such as syntax to be recognized as an entity reference) is treated as literal text, and needs to be appropriately escaped by the implementation when it is written out. In order to assign an attribute value that contains entity references, the user must create an Attr node plus any Text and EntityReference nodes, build the appropriate subtree, and use setAttributeNode to assign it as the value of an attribute.
To set an attribute with a qualified name and namespace URI, use the setAttributeNS method.

Parameters

name	The name of the attribute to create or alter.
value	Value to set in string form.

Throws

DOMException	INVALID_CHARACTER_ERR: Raised if the specified name is not an XML name according to the XML version in use specified in the Document.xmlVersion attribute. NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.

public abstract void setAttributeNS (String namespaceURI, String qualifiedName, String value)

Adds a new attribute. If an attribute with the same local name and namespace URI is already present on the element, its prefix is changed to be the prefix part of the qualifiedName, and its value is changed to be the value parameter. This value is a simple string; it is not parsed as it is being set. So any markup (such as syntax to be recognized as an entity reference) is treated as literal text, and needs to be appropriately escaped by the implementation when it is written out. In order to assign an attribute value that contains entity references, the user must create an Attr node plus any Text and EntityReference nodes, build the appropriate subtree, and use setAttributeNodeNS or setAttributeNode to assign it as the value of an attribute.
Per [XML Namespaces] , applications must use the value null as the namespaceURI parameter for methods if they wish to have no namespace.

Parameters

namespaceURI	The namespace URI of the attribute to create or alter.
qualifiedName	The qualified name of the attribute to create or alter.
value	The value to set in string form.

Throws

DOMException

INVALID_CHARACTER_ERR: Raised if the specified qualified name is not an XML name according to the XML version in use specified in the Document.xmlVersion attribute. NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. NAMESPACE_ERR: Raised if the qualifiedName is malformed per the Namespaces in XML specification, if the qualifiedName has a prefix and the namespaceURI is null, if the qualifiedName has a prefix that is "xml" and the namespaceURI is different from " http://www.w3.org/XML/1998/namespace", if the qualifiedName or its prefix is "xmlns" and the namespaceURI is different from "http://www.w3.org/2000/xmlns/", or if the namespaceURI is "http://www.w3.org/2000/xmlns/" and neither the qualifiedName nor its prefix is "xmlns". NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

public abstract Attr setAttributeNode (Attr newAttr)

Adds a new attribute node. If an attribute with that name ( nodeName) is already present in the element, it is replaced by the new one. Replacing an attribute node by itself has no effect.
To add a new attribute node with a qualified name and namespace URI, use the setAttributeNodeNS method.

Parameters

newAttr	The Attr node to add to the attribute list.

Returns

• If the newAttr attribute replaces an existing attribute, the replaced Attr node is returned, otherwise null is returned.

Throws

DOMException	WRONG_DOCUMENT_ERR: Raised if newAttr was created from a different document than the one that created the element. NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. INUSE_ATTRIBUTE_ERR: Raised if newAttr is already an attribute of another Element object. The DOM user must explicitly clone Attr nodes to re-use them in other elements.

public abstract Attr setAttributeNodeNS (Attr newAttr)

Adds a new attribute. If an attribute with that local name and that namespace URI is already present in the element, it is replaced by the new one. Replacing an attribute node by itself has no effect.
Per [XML Namespaces] , applications must use the value null as the namespaceURI parameter for methods if they wish to have no namespace.

Parameters

newAttr	The Attr node to add to the attribute list.

Returns

• If the newAttr attribute replaces an existing attribute with the same local name and namespace URI, the replaced Attr node is returned, otherwise null is returned.

Throws

DOMException

WRONG_DOCUMENT_ERR: Raised if newAttr was created from a different document than the one that created the element. NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. INUSE_ATTRIBUTE_ERR: Raised if newAttr is already an attribute of another Element object. The DOM user must explicitly clone Attr nodes to re-use them in other elements. NOT_SUPPORTED_ERR: May be raised if the implementation does not support the feature "XML" and the language exposed through the Document does not support XML Namespaces (such as [HTML 4.01]).

public abstract void setIdAttribute (String name, boolean isId)

If the parameter isId is true, this method declares the specified attribute to be a user-determined ID attribute . This affects the value of Attr.isId and the behavior of Document.getElementById, but does not change any schema that may be in use, in particular this does not affect the Attr.schemaTypeInfo of the specified Attr node. Use the value false for the parameter isId to undeclare an attribute for being a user-determined ID attribute.
To specify an attribute by local name and namespace URI, use the setIdAttributeNS method.

Parameters

name	The name of the attribute.
isId	Whether the attribute is a of type ID.

Throws

DOMException	NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. NOT_FOUND_ERR: Raised if the specified node is not an attribute of this element.

public abstract void setIdAttributeNS (String namespaceURI, String localName, boolean isId)

If the parameter isId is true, this method declares the specified attribute to be a user-determined ID attribute . This affects the value of Attr.isId and the behavior of Document.getElementById, but does not change any schema that may be in use, in particular this does not affect the Attr.schemaTypeInfo of the specified Attr node. Use the value false for the parameter isId to undeclare an attribute for being a user-determined ID attribute.

Parameters

namespaceURI	The namespace URI of the attribute.
localName	The local name of the attribute.
isId	Whether the attribute is a of type ID.

Throws

DOMException	NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. NOT_FOUND_ERR: Raised if the specified node is not an attribute of this element.

public abstract void setIdAttributeNode (Attr idAttr, boolean isId)

If the parameter isId is true, this method declares the specified attribute to be a user-determined ID attribute . This affects the value of Attr.isId and the behavior of Document.getElementById, but does not change any schema that may be in use, in particular this does not affect the Attr.schemaTypeInfo of the specified Attr node. Use the value false for the parameter isId to undeclare an attribute for being a user-determined ID attribute.

Parameters

idAttr	The attribute node.
isId	Whether the attribute is a of type ID.

Throws

DOMException	NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly. NOT_FOUND_ERR: Raised if the specified node is not an attribute of this element.