use My::Customer;
use CGI;
my $cgi = CGI->new;
my $cust_id = $cgi->param('customer_id');
error_page("Bad customer id") 
  unless $cust_id && $cust_id =~ /^\d_/;
my $email = $cgi->param('email');
# validate email
my $cust = My::Customer->load_from_id($cust_id);
$cust->email($email);
$cust->save;

##</code><code>##

use Class::CGI
  handlers => {
    customer => 'Class::CGI::Customer'
  };
my $cgi   = Class::CGI->new;
my $cust  = $cgi->param('customer');
my $email = $cgi->param('email');
# validate email
$cust->email($email);
$cust->save;