File Extension PHP4 File Format PHP Script PHP4 stands for PHP Script. This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question call php script from CL - slow Unable to browse local intranet PHP site MYSQL/PHP based CMS (Mambo,Joomla) on the 400.