The DOMEntity object Represents an entity declared in the document type declaration (DTD).
The DOMDocumentType object inherits the properties and methods of the DOMNode object.
||The public identifier associated with the entity, if specified. If the public identifier is not specified, it is null.
||The system identifier associated with the entity, if specified. Or null, if not specified.|
||For unparsed entities, the name of the notation for the entity. For parsed entities this is null.|