When you surf the internet, your web browser tells websites all kinds of information about you. Here are the variables your web browser provided us just now when you accessed this page:
HTTP_ACCEPT
HTTP_ACCEPT_LANGUAGE
HTTP_COOKIE
HTTP_REFERER
HTTP_USER_AGENT
HTTPS
HTTPS_KEYSIZE
HTTPS_SECRETKEYSIZE
HTTPS_SERVER_ISSUER
HTTPS_SERVER_SUBJECT
LOGON_USER
PATH_INFO
QUERY_STRING
REMOTE_ADDR
REMOTE_HOST
REMOTE_USER
REQUEST_METHOD
SCRIPT_NAME
SERVER_NAME
SERVER_PORT
SERVER_PORT_SECURE
SERVER_PROTOCOL
URL