function numDaysMonth(month,year) {
  var days = 31;
  if (month == 4 || month == 6 || month == 9 || month == 11) 
          days = 30;
  if (month == 2 && (year/ 4) != Math.floor (year/4)) 
          days = 28;
  if (month == 2 && (year/ 4) == Math.floor (year/4))
          days = 29;
  return days;
}