Using Javascript to validate South African ID Numbers

Dave — Tue, 02 Mar 2010 13:00:21 +0000

I have just finished a neat little client side ID number validation script that ensures that the ID number passed is:

Numeric,
is 13 Digits long,
has a valid date with the first 6 characters
and passes the Luhn algorithm test.

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)) &amp;&amp; (tempDate.getMonth() == idnumber.substring(2, 4) - 1) &amp;&amp; (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 &lt; 13; ++i) {

tempTotal = parseInt(idnumber.charAt(i)) * multiplier;

if (tempTotal &gt; 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;

}

Dave Russell » Validation

Using Javascript to validate South African ID Numbers