(PHP 4 >= 4.1.0, PHP 5, PHP 7) Session variables

(PHP 4 >= 4.1.0, PHP 5, PHP 7) HTTP Request variables

(PHP 4 >= 4.0.4, PHP 5, PHP 7) HTTP response headers

(PHP 4 >= 4.1.0, PHP 5, PHP 7) HTTP File Upload variables

(PHP 4, PHP 5, PHP 7) The number of arguments passed to script

(PHP 4, PHP 5) Raw POST data

(PHP 4, PHP 5, PHP 7) References all variables available in global scope

(PHP 4 >= 4.1.0, PHP 5, PHP 7) HTTP Cookies An

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Server and execution environment information

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Environment variables