PHP - Predefined Variables
PHP provides a large number of predefined variables to all scripts which it runs. The variables represent everything from external variables to built-in environment variables, last error messages to last retrieved headers.
List of Predefined Variables
| Variable | Description |
|---|---|
| Superglobals | Built-in variables that are always available in all scopes |
| $GLOBALS | References all variables available in global scope |
| $_SERVER | Server and execution environment information |
| $_GET | HTTP GET variables |
| $_POST | HTTP POST variables |
| $_FILES | HTTP File Upload variables |
| $_REQUEST | HTTP Request variables |
| $_SESSION | Session variables |
| $_ENV | Environment variables |
| $_COOKIE | HTTP Cookies |
| $php_errormsg | The previous error message |
| $http_response_header | HTTP response headers |
| $argc | The number of arguments passed to script |
| $argv | Array of arguments passed to script |
