$_SERVER
$_SERVER['PHP_SELF']
$_SERVER['GATEWAY_INTERFACE']
$_SERVER['SERVER_ADDR']
$_SERVER['SERVER_NAME']
$_SERVER['SERVER_SOFTWARE']
$_SERVER['SERVER_PROTOCOL']
$_SERVER['REQUEST_METHOD']
$_SERVER['REQUEST_TIME']
$_SERVER['QUERY_STRING']
$_SERVER['DOCUMENT_ROOT']
$_SERVER['HTTP_ACCEPT']
$_SERVER['HTTP_ACCEPT_CHARSET']
$_SERVER['HTTP_ACCEPT_ENCODING']
$_SERVER['HTTP_ACCEPT_LANGUAGE']
$_SERVER['HTTP_CONNECTION']
$_SERVER['HTTP_HOST']
$_SERVER['HTTP_REFERER']
$_SERVER['HTTP_USER_AGENT']
$_SERVER['HTTPS']
$_SERVER['REMOTE_ADDR']
$_SERVER['REMOTE_HOST']
$_SERVER['REMOTE_PORT']
$_SERVER['REMOTE_USER']
$_SERVER['REDIRECT_REMOTE_USER']
$_SERVER['SCRIPT_FILENAME']
$_SERVER['SERVER_ADMIN']
$_SERVER['SERVER_PORT']
$_SERVER['SERVER_SIGNATURE']
$_SERVER['PATH_TRANSLATED']
$_SERVER['SCRIPT_NAME']
$_SERVER['REQUEST_URI']
$_SERVER['PHP_AUTH_DIGEST']
$_SERVER['PHP_AUTH_USER']
$_SERVER['PHP_AUTH_PW']
$_SERVER['AUTH_TYPE']
$_SERVER['PATH_INFO']
$_SERVER['ORIG_PATH_INFO']
$_SERVER['HTTP_COOKIE']