$_SERVER["SCRIPT_FILENAME"] // server path to file
$_SERVER["SCRIPT_NAME"] // path to file from web root
$_SERVER["REMOTE_ADDR"] // user's IP address
$_SERVER["QUERY_STRING"] // query string in URL
$_SERVER["DOCUMENT_ROOT"] // server path to web root
$_SERVER["HTTP_HOST"]; // server host name (domain)

Environment Variables

PHP