$_SERVER is a PHP super global variable which holds information about headers, paths, and script locations.
Example
<?php
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
echo $_SERVER['HTTP_HOST'];
echo "<br>";
echo $_SERVER['HTTP_REFERER'];
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME'];
?>The following table lists the most important elements that can go inside $_SERVER:
| Element/Code | Description |
|---|---|
| $_SERVER[‘PHP_SELF’] | Returns the filename of the currently executing script |
| $_SERVER[‘GATEWAY_INTERFACE’] | Returns the version of the Common Gateway Interface (CGI) the server is using |
| $_SERVER[‘SERVER_ADDR’] | Returns the IP address of the host server |
| $_SERVER[‘SERVER_NAME’] | Returns the name of the host server (such as www.w3schools.com) |
| $_SERVER[‘SERVER_SOFTWARE’] | Returns the server identification string (such as Apache/2.2.24) |
| $_SERVER[‘SERVER_PROTOCOL’] | Returns the name and revision of the information protocol (such as HTTP/1.1) |
| $_SERVER[‘REQUEST_METHOD’] | Returns the request method used to access the page (such as POST) |
| $_SERVER[‘REQUEST_TIME’] | Returns the timestamp of the start of the request (such as 1377687496) |
| $_SERVER[‘QUERY_STRING’] | Returns the query string if the page is accessed via a query string |
| $_SERVER[‘HTTP_ACCEPT’] | Returns the Accept header from the current request |
| $_SERVER[‘HTTP_ACCEPT_CHARSET’] | Returns the Accept_Charset header from the current request (such as utf-8,ISO-8859-1) |
| $_SERVER[‘HTTP_HOST’] | Returns the Host header from the current request |
| $_SERVER[‘HTTP_REFERER’] | Returns the complete URL of the current page (not reliable because not all user-agents support it) |
| $_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[‘SCRIPT_FILENAME’] | Returns the absolute pathname of the currently executing script |
| $_SERVER[‘SERVER_ADMIN’] | Returns the value given to the SERVER_ADMIN directive in the web server configuration file (if your script runs on a virtual host, it will be the value defined for that virtual host) (such as someone@w3schools.com) |
| $_SERVER[‘SERVER_PORT’] | Returns the port on the server machine being used by the web server for communication (such as 80) |
| $_SERVER[‘SERVER_SIGNATURE’] | Returns the server version and virtual host name which are added to server-generated pages |
| $_SERVER[‘PATH_TRANSLATED’] | Returns the file system based path to the current script |
| $_SERVER[‘SCRIPT_NAME’] | Returns the path of the current script |
| $_SERVER[‘SCRIPT_URI’] | Returns the URI of the current page |
