DOMNode->isDefaultNamespace() Checks if the specified namespaceURI is the default namespace or not &reftitle.description; DOMNode boolisDefaultNamespace stringnamespaceURI Tells whether namespaceURI is the default namespace. &reftitle.parameters; namespaceURI The namespace URI to look for. &reftitle.returnvalues; Return &true; if namespaceURI is the default namespace, &false; otherwise.