case 4:
case 8:
case 11:
if (last_character != '-') {
value = value.substring(0,
current_length - 1);
}
break;
default:
if (!/\d/.test(last_character)) {
value = value.substring(0,
current_length - 1);
}
}
if (current_length > 12) {
value = value.substring(0, current_length

• 1);
  }
  current_length = value.length;
  switch (current_length) {
  case 3:
  case 7:
  case 10:
  value += "-";
  }
  input_object.value = value;
  }
  }
  
  
  

  Form management

  
  
  
  Enter here a serial number in the pattern XXX-XXX-XXX, where each X is a digit: id="serial" type='text' size='12' onkeyup="correct();">.