Graham The_Netter The basics to do the same thing would be something like this
you have your form which is also in the script
and for example it sets a variable called username
This script also sets a cookie to remember the username between visits
demo of this script HERE

<!--parser:xtscript--> # Get the username from the form get username # Check for a cookie or default to the entered name from the form var $username = call cookie::get $name=mycookie;$default=$username # If the username is set refresh or create the cookie and output the username if $username call cookie::set $name=mycookie; $val=$username; $expire=99999999;$force_current=1; print <span class="">$username</span> else # Show the form var $self=<xt:url /> print {{ <form action="$self" method="post"> <input name="username" /> <input type="submit" /> </form>}} endif <!--/parser:xtscript-->

first time it shows the form
second time or on return visits it shows the username