1) Check if cookie exists and is valid
2) If it doesn't exist or if it's incorrect, print html form
3) From HTML form set a cookie when they click submit

##</code><code>##

If a cookie exists {
if {#check for validity  }
else { #exit}
}
else {
# since no cookie or no valid cookie was found, print HTML form asking for input
#
# now that we have information, make a cookie, set it and refresh the page
}