public interface NamedNodeMap
Objects implementing the 
NamedNodeMap interface are used to
 represent collections of nodes that can be accessed by name. Note that
 NamedNodeMap does not inherit from NodeList;
 NamedNodeMaps are not maintained in any particular order.
 Objects contained in an object implementing NamedNodeMap may
 also be accessed by an ordinal index, but this is simply to allow
 convenient enumeration of the contents of a NamedNodeMap,
 and does not imply that the DOM specifies an order to these Nodes.
 NamedNodeMap objects in the DOM are live.
 
See also the Document Object Model (DOM) Level 3 Core Specification.
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Method SummaryModifier and Type Method Description intgetLength()The number of nodes in this map.NodegetNamedItem(String name)Retrieves a node specified by name.NodegetNamedItemNS(String namespaceURI, String localName)Retrieves a node specified by local name and namespace URI.Nodeitem(int index)Returns theindexth item in the map.NoderemoveNamedItem(String name)Removes a node specified by name.NoderemoveNamedItemNS(String namespaceURI, String localName)Removes a node specified by local name and namespace URI.NodesetNamedItem(Node arg)Adds a node using itsnodeNameattribute.NodesetNamedItemNS(Node arg)Adds a node using itsnamespaceURIandlocalName.
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Method Details- 
getNamedItemRetrieves a node specified by name.- Parameters:
- name- The- nodeNameof a node to retrieve.
- Returns:
- A Node(of any type) with the specifiednodeName, ornullif it does not identify any node in this map.
 
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setNamedItemAdds a node using itsnodeNameattribute. If a node with that name is already present in this map, it is replaced by the new one. Replacing a node by itself has no effect.
 As thenodeNameattribute is used to derive the name which the node must be stored under, multiple nodes of certain types (those that have a "special" string value) cannot be stored as the names would clash. This is seen as preferable to allowing nodes to be aliased.- Parameters:
- arg- A node to store in this map. The node will later be accessible using the value of its- nodeNameattribute.
- Returns:
- If the new Nodereplaces an existing node the replacedNodeis returned, otherwisenullis returned.
- Throws:
- DOMException- WRONG_DOCUMENT_ERR: Raised if- argwas created from a different document than the one that created this map.
 NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
 INUSE_ATTRIBUTE_ERR: Raised if- argis an- Attrthat is already an attribute of another- Elementobject. The DOM user must explicitly clone- Attrnodes to re-use them in other elements.
 HIERARCHY_REQUEST_ERR: Raised if an attempt is made to add a node doesn't belong in this NamedNodeMap. Examples would include trying to insert something other than an Attr node into an Element's map of attributes, or a non-Entity node into the DocumentType's map of Entities.
 
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removeNamedItemRemoves a node specified by name. When this map contains the attributes attached to an element, 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.- Parameters:
- name- The- nodeNameof the node to remove.
- Returns:
- The node removed from this map if a node with such a name exists.
- Throws:
- DOMException- NOT_FOUND_ERR: Raised if there is no node named- namein this map.
 NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
 
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itemReturns theindexth item in the map. Ifindexis greater than or equal to the number of nodes in this map, this returnsnull.- Parameters:
- index- Index into this map.
- Returns:
- The node at the indexth position in the map, ornullif that is not a valid index.
 
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getLengthint getLength()The number of nodes in this map. The range of valid child node indices is0tolength-1inclusive.
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getNamedItemNSRetrieves a node specified 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 node to retrieve.
- localName- The local name of the node to retrieve.
- Returns:
- A Node(of any type) with the specified local name and namespace URI, ornullif they do not identify any node in this map.
- 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]).
- Since:
- 1.4, DOM Level 2
 
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setNamedItemNSAdds a node using itsnamespaceURIandlocalName. If a node with that namespace URI and that local name is already present in this map, it is replaced by the new one. Replacing a 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:
- arg- A node to store in this map. The node will later be accessible using the value of its- namespaceURIand- localNameattributes.
- Returns:
- If the new Nodereplaces an existing node the replacedNodeis returned, otherwisenullis returned.
- Throws:
- DOMException- WRONG_DOCUMENT_ERR: Raised if- argwas created from a different document than the one that created this map.
 NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
 INUSE_ATTRIBUTE_ERR: Raised if- argis an- Attrthat is already an attribute of another- Elementobject. The DOM user must explicitly clone- Attrnodes to re-use them in other elements.
 HIERARCHY_REQUEST_ERR: Raised if an attempt is made to add a node doesn't belong in this NamedNodeMap. Examples would include trying to insert something other than an Attr node into an Element's map of attributes, or a non-Entity node into the DocumentType's map of Entities.
 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]).
- Since:
- 1.4, DOM Level 2
 
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removeNamedItemNSRemoves a node specified by local name and namespace URI. A removed attribute may be known to have a default value when this map contains the attributes attached to an element, as returned by the attributes attribute of theNodeinterface. If so, an attribute immediately appears containing the default value as well as the corresponding namespace URI, local name, and prefix when applicable.
 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 node to remove.
- localName- The local name of the node to remove.
- Returns:
- The node removed from this map if a node with such a local name and namespace URI exists.
- Throws:
- DOMException- NOT_FOUND_ERR: Raised if there is no node with the specified- namespaceURIand- localNamein this map.
 NO_MODIFICATION_ALLOWED_ERR: Raised if this map 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]).
- Since:
- 1.4, DOM Level 2
 
 
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