# inputBox( $url, $msgid, $action, \%data )
sub inputBox{
  my $data = $_[3];
  # some code here...
  # some processing here...
  return $result . map this($_),
    # hash de-ref and slicing at the same time...
    # however, can't do this with $_[3], syntax error.
    @$data{'a','b','c','d'};