my $action = $query->param('ACTION');

unless(defined($action))
{
 $action = 'default';
}

##</code><code>##

if($action eq 'delete')
{
 $confirmed = $query->param('CONFIRMED')
 if($confirmed eq 'yes')
 {
  # do stuff
 }
 else
 {
  # do other stuff
 }
}