function ValidateIDnumber(idnumber) {
//1. numeric and 13 digits
if (isNaN(idnumber) || (idnumber.length != 13)) { return false; }
//2. first 6 numbers is a valid date
var tempDate = new Date(idnumber.substring(0, 2), idnumber.substring(2, 4) - 1, idnumber.substring(4, 6));
if (!((tempDate.getYear() == idnumber.substring(0, 2)) && (tempDate.getMonth() == idnumber.substring(2, 4) - 1) && (tempDate.getDate() == idnumber.substring(4, 6)))) { return false; }
//3. luhn formula
var tempTotal = 0; var checkSum = 0; var multiplier = 1;
for (var i = 0; i < 13; ++i) {
tempTotal = parseInt(idnumber.charAt(i)) * multiplier;
if (tempTotal > 9) { tempTotal = parseInt(tempTotal.toString().charAt(0)) + parseInt(tempTotal.toString().charAt(1)); }
checkSum = checkSum + tempTotal;
multiplier = (multiplier % 2 == 0) ? 1 : 2;
}
if ((checkSum % 10) == 0) { return true };
return false;
}