Element/Code Description
$_SERVER['PHP_SELF'] Returns the file name of the currently executing script.
$_SERVER['GATEWAY_INTERFACE'] Returns the version of the CGI specification used by the server.
$_SERVER['SERVER_ADDR'] Returns the IP address of the server where the script is currently running.
$_SERVER['SERVER_NAME'] Returns the host name of the server where the script is currently running (such as www.w3school.com.cn).
$_SERVER['SERVER_SOFTWARE'] Returns the server identification string (such as Apache/2.2.24).
$_SERVER['SERVER_PROTOCOL'] Returns the name and version of the communication protocol when the page was requested (for example, "HTTP/1.0").
$_SERVER['REQUEST_METHOD'] Returns the request method used to access the page (such as POST).
$_SERVER['REQUEST_TIME'] Returns the timestamp when the request started (for example, 1577687494).
$_SERVER['QUERY_STRING'] Returns the query string, if this page is accessed through the query string.
$_SERVER['HTTP_ACCEPT'] Returns the request headers 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 full URL of the current page (unreliable because not all user agents support it).
$_SERVER['HTTPS'] Whether to query the script through the secure HTTP protocol.
$_SERVER['REMOTE_ADDR'] Returns the IP address of the user browsing the current page.
$_SERVER['REMOTE_HOST'] Returns the host name of the user browsing the current page.
$_SERVER['REMOTE_PORT'] Returns the port number used to connect to the web server on the user's machine.
$_SERVER['SCRIPT_FILENAME'] Returns the absolute path of the currently executing script.
$_SERVER['SERVER_ADMIN'] This value specifies the SERVER_ADMIN parameter in the Apache server configuration file.
$_SERVER['SERVER_PORT'] The port used by the web server. The default value is "80".
$_SERVER['SERVER_SIGNATURE'] Returns the server version and virtual host name.
$_SERVER['PATH_TRANSLATED'] The base path of the file system (not the document root directory) where the current script is located.
$_SERVER['SCRIPT_NAME'] Returns the path of the current script.
$_SERVER['SCRIPT_URI'] Returns the URI of the current page.
The above table lists the most important elements you can access in $_SERVER