Superglobals were introduced in PHP 4.1.0. They are built-in variables that are always available in all scopes. You can access them from any function, class or file without having to do anything special.
The PHP superglobal variables are:
$GLOBALS - Contains all global variables, including other superglobals.
$_SERVER - Contains information about the web server and the request made to it.
$_REQUEST - Contains $_GET, $_POST, and possibly $_COOKIE variables.
$_POST - Contains variables sent via an HTTP POST request.
$_GET - Contains variables sent via an HTTP GET request.
$_FILES - Contains variables sent via an HTTP POST file upload.
$_ENV - Contains all environment variables set by the web server.
$_COOKIE - Contains variables sent via HTTP cookies.
$_SESSION - Contains variables stored in a user's session.
PHP $_SERVER Global Variable
$_SERVER is a PHP super global variable which holds information about headers, paths, and script locations.
- $_SERVER['SERVER_ADDR']: Returns the IP address of the host server
- $_SERVER['SERVER_NAME']: Returns the name of the host server
- $_SERVER['REQUEST_METHOD']: Returns the request method used to access the page
- $_SERVER['QUERY_STRING']: Returns the query string if the page is accessed via a query string
- $_SERVER['HTTP_HOST']: Returns the Host header from the current request
- $_SERVER['HTTPS']: Is the script queried through a secure HTTP protocol
- $_SERVER['REMOTE_ADDR']: Returns the IP address from where the user is viewing the current page
- $_SERVER['REMOTE_HOST']: Returns the Host name from where the user is viewing the current page
- $_SERVER['REMOTE_PORT']: Returns the port being used on the user's machine to communicate with the web server
- $_SERVER['SERVER_PORT']: Returns the port on the server machine being used by the web server for communication
- $_SERVER['SCRIPT_NAME']: Returns the path of the current script
- $_SERVER['SCRIPT_URI']: Returns the URI of the current page