(no version information, might be only in CVS)
DomDocument->doctype --
Returns the document type
说明
domdocumenttype
DomDocument->doctype ( void )
This function returns an object of class
DomDocumentType. In versions of
PHP before 4.3 this has been the class Dtd,
but the DOM Standard does not know such a class.
See also the methods of class DomDocumentType.