Element interface
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.
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In DOM Level 2, the method normalize is inherited from the Node interface where it was moved.
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tagName attribute
The name of the element. 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.
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tagName
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Access
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read-only
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Returns
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String
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getAttribute method
Retrieves an attribute value by name.
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getAttribute name
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Parameters
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String name
The name of the attribute to retrieve.
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Returns
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String. The Attr value as a string, or the empty string if that attribute does not have a specified or default value.
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getAttributeNS method
Retrieves an attribute value by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
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getAttributeNS namespaceURI localName
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Parameters
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String namespaceURI
The namespace URI of the attribute to retrieve.
String localName
The local name of the attribute to retrieve.
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Returns
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String. The Attr value as a string, or the empty string if that attribute does not have a specified or default value.
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getAttributeNode method
Retrieves an attribute node by name.
To retrieve an attribute node by qualified name and namespace URI, use the getAttributeNodeNS method.
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getAttributeNode name
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Parameters
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String name
The name (nodeName) of the attribute to retrieve.
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Returns
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Attr. The Attr node with the specified name (nodeName) or null if there is no such attribute.
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getAttributeNodeNS method
Retrieves an Attr node by local name and namespace URI. HTML-only DOM implementations do not need to implement this method.
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getAttributeNodeNS namespaceURI localName
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Parameters
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String namespaceURI
The namespace URI of the attribute to retrieve.
String localName
The local name of the attribute to retrieve.
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Returns
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Attr. The Attr node with the specified attribute local name and namespace URI or null if there is no such attribute.
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getElementsByTagName method
Returns a NodeList of all descendant Elements with a given tag name, in the order in which they are encountered in a preorder traversal of this Element tree.
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getElementsByTagName name
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Parameters
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String name
The name of the tag to match on. The special value "*" matches all tags.
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Returns
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NodeList. A list of matching Element nodes.
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getElementsByTagNameNS method
Returns a NodeList of all the descendant Elements with a given local name and namespace URI in the order in which they are encountered in a preorder traversal of this Element tree.
HTML-only DOM implementations do not need to implement this method.
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getElementsByTagNameNS namespaceURI localName
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Parameters
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String namespaceURI
The namespace URI of the elements to match on. The special value "*" matches all namespaces.
String localName
The local name of the elements to match on. The special value "*" matches all local names.
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Returns
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NodeList. A new NodeList object containing all the matched Elements.
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hasAttribute method
Returns true when an attribute with a given name is specified on this element or has a default value, false otherwise.
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hasAttribute name
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Parameters
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String name
The name of the attribute to look for.
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Returns
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trueboolean. if an attribute with the given name is specified on this element or has a default value, false otherwise.
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hasAttributeNS method
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. HTML-only DOM implementations do not need to implement this method.
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hasAttributeNS namespaceURI localName
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Parameters
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String namespaceURI
The namespace URI of the attribute to look for.
String localName
The local name of the attribute to look for.
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Returns
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trueboolean. if an attribute with the given local name and namespace URI is specified or has a default value on this element, false otherwise.
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removeAttribute method
Removes an attribute by name. If the removed attribute is known to have a default value, an attribute immediately appears containing the default value as well as the corresponding namespace URI, local name, and prefix when applicable.
To remove an attribute by local name and namespace URI, use the removeAttributeNS method.
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removeAttribute name
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Parameters
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String name
The name of the attribute to remove.
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Returns
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void
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Throws
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DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
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removeAttributeNS method
Removes an attribute by local name and namespace URI. If the removed attribute has a default value it is immediately replaced. The replacing attribute has the same namespace URI and local name, as well as the original prefix.
HTML-only DOM implementations do not need to implement this method.
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removeAttributeNS namespaceURI localName
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Parameters
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String namespaceURI
The namespace URI of the attribute to remove.
String localName
The local name of the attribute to remove.
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Returns
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void
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Throws
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DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
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removeAttributeNode method
Removes the specified attribute node. If the removed Attr has a default value it is immediately replaced. The replacing attribute has the same namespace URI and local name, as well as the original prefix, when applicable.
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removeAttributeNode oldAttr
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Parameters
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Attr oldAttr
The Attr node to remove from the attribute list.
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Returns
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Attr. The Attr node that was removed.
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Throws
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DOMException
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NOT_FOUND_ERR: Raised if oldAttr is not an attribute of the element.
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setAttribute method
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.
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setAttribute name value
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Parameters
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String name
The name of the attribute to create or alter.
String value
Value to set in string form.
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Returns
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void
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Throws
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DOMException
INVALID_CHARACTER_ERR: Raised if the specified name contains an illegal character.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
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setAttributeNS method
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.
HTML-only DOM implementations do not need to implement this method.
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setAttributeNS namespaceURI qualifiedName value
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Parameters
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String namespaceURI
The namespace URI of the attribute to create or alter.
String qualifiedName
The qualified name of the attribute to create or alter.
String value
The value to set in string form.
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Returns
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void
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Throws
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DOMException
INVALID_CHARACTER_ERR: Raised if the specified qualified name contains an illegal character.
NO_MODIFICATION_ALLOWED_ERR: Raised if this node is readonly.
NAMESPACE_ERR: Raised if the qualifiedName is malformed, 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 the xml namespace, or if the qualifiedName is "xmlns" and the namespaceURI is different from the xml namespace.
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setAttributeNode method
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.
To add a new attribute node with a qualified name and namespace URI, use the setAttributeNodeNS method.
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setAttributeNode newAttr
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Parameters
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Attr newAttr
The Attr node to add to the attribute list.
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Returns
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Attr. If the newAttr attribute replaces an existing attribute, the replaced Attr node is returned, otherwise null is returned.
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Throws
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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.
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setAttributeNodeNS method
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.
HTML-only DOM implementations do not need to implement this method.
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setAttributeNodeNS newAttr
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Parameters
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Attr newAttr
The Attr node to add to the attribute list.
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Returns
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Attr. 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.
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Throws
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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.
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