# present result in a table
print '<table border="1" cellspacing="0" cellpadding="5">';
my $n = 0;
for  (sort keys %list){
  ++$n;
  print qq!<tr>
    <td>$n</td>
    <td>$_</td>
    <td>$list{$_}</td>
  </tr>!;
}
print '</table><br/>';
print scalar localtime;
print end_html;

# your email routine here
sub send_to {
  my $to = shift;
  my $result = "Log or error for $to";
#  $mail{To} = $to;
#  if ( sendmail(%mail) ){
#    $result = $Mail::Sendmail::log;
#  } else {
#    $result = $Mail::Sendmail::error;
#  }
  return $result; # either log or error msg
}

# check address is valid
sub is_valid {
  my $addr = shift;
  # make checks here as 
  # complicated  as required
  if ($addr =~ /\@/){
    return 1;
  } 
  return 0;  
}