Crea un nuevo objeto DOMXPath.
document
El objeto DOMDocument asociado con el objeto DOMXPath.
registerNodeNS
Whether to automatically register the in-scope namespace prefixes of the context node to the DOMXPath object. This can be used to avoid needing to call DOMXPath::registerNamespace() manually for each in-scope namespaces. When a namespace prefix conflict exists, only the nearest descendant namespace prefix is registered.