Variable Contains Example
$_SERVER['PHP_SELF'] The current script. /l.php
$_SERVER['HTTP_USER_AGENT'] The name and version of the client. Mozilla/4.6 ?(X11; I;Linux2.2. 6-15apmac ppc)
$_SERVER['REMOTE_ADDR'] The IP address of the client. 192.152.55.35
$_SERVER['REQUEST_METHOD'] Whether the request was GET or POST. POST
$_SERVER['QUERY_STRING'] For GET requests, the encoded data sent appended to the URL. name=matt&address=unknown
$_SERVER['REQUEST_URI'] The full address of the request, including query string. /phpbook/source/listing10.1.php? name=matt
$_SERVER['HTTP_REFERER'] The address of the page from which the request was made. http://p24.corrosive.co.uk/ref.html