hello bhavesh,
found this on php.net:
"in php.ini: session.cookie_lifetime specifies the lifetime of the cookie in seconds which is sent to the browser. The value 0 means
"until the browser is closed." Defaults to 0."
if you are not using session-cookies you
might store the unix-timestamp in a
variable and always check this later for
too much time having passed since session-
registration...
hth
chris