function verifyDOB(dateStr) {

  var day = dateStr.split("/")[0];
  var month = dateStr.split("/")[1];
  var year = dateStr.split("/")[2];

  var dayOk;
  var monthOk;
  var yearOk;

  dateOk = false;
  monthOk = false;
  yearOk = true;

  if (day == "1" || day == "2" || day == "3" || day == "4" || day == "5" ||
      day == "6" || day == "7" || day == "8" || day == "9" || day == "10" ||
      day == "01" || day == "02" || day == "03" || day == "04" || day == "05" ||
      day == "06" || day == "07" || day == "08" || day == "09" || day == "10" ||
      day == "11" || day == "12" || day == "13" || day == "14" || day == "15" ||
      day == "16" || day == "17" || day == "18" || day == "19" || day == "20" ||
      day == "21" || day == "22" || day == "23" || day == "24" || day == "25" ||
      day == "26" || day == "27" || day == "27" || day == "29" || day == "30" ||
      day == "31") {
    dayOk = true;
  }

  if (month == "1" || month == "2" || month == "3" || month == "4" || month == "5" ||
      month == "6" || month == "7" || month == "8" || month == "9" || month == "10" ||
      month == "01" || month == "02" || month == "03" || month == "04" || month == "05" ||
      month == "06" || month == "07" || month == "08" || month == "09" || month == "10" ||
      month == "11" || month == "12") {
    monthOk = true;
  }

  var dateOk;
  if (dayOk == true && monthOk == true && yearOk == true) {
    dateOk = true;
  } else {
    dateOk = false;
  }

  if (!dateOk) {
    alert("Please enter a correct date of birth");
  }

  return dateOk;
}