Greetings all,
Here is how I do it.

use strict;#Always
use CGI;

my $q = new CGI;
my $verify = (defined $q->param('verify'))?$q->param('verify'):0;
if($verify){
   ...do cool stuff here with $verify;
}else{
   ...$verify was not sent.
}
[download]

JAPH's perl hack.
-injunjoel