Validate credit card by using jquery

Question

How can i validate credit/debit card by using jquery/javascript?

I have tried to do by using Luhn algorithm.

function checkLuhn(input) { 
var sum = 0;
var numdigits = input.length;
var parity = numdigits % 2;

for(var i=0; i < numdigits; i++) {
     var digit = parseInt(input.charAt(i))
     if(i % 2 == parity) digit *= 2;
     if(digit > 9) 
        digit -= 9;
     sum += digit;
} 
return (sum % 10) == 0;

}

Do you have any good/simpler way to do it?

Thanks in advance

http://stackoverflow.com/questions/13921456/jquery-validator-credit-card-number-type-match is which you need. — Lumi Lu, Mar 23 '15 at 12:22
Exist a jQuery plugin to do that:[jQuery Credit Card Validator](http://jquerycreditcardvalidator.com) — Teo, Mar 23 '15 at 12:32

score 1 · Accepted Answer · answered Mar 23 '15 at 12:29

You can prevent user typing incorrect value in the first place using jQuery Mask Plugin

$('#debit').mask('0000 0000 0000 0000');

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="http://igorescobar.github.io/jQuery-Mask-Plugin/js/jquery.mask.min.js"></script>

<input type="text" id="debit">

KungWaz · Answer 2 · 2015-03-24T07:00:49.100

This is how I did it with Luhn-algorithm and card number length (we only support specific cards that have 16 digits):

// Luhn-algorithm check
function checkCardNumber(number) {
    var sumTable = [
            [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
            [0, 2, 4, 6, 8, 1, 3, 5, 7, 9]
        ],
        sum = 0,
        flip = 0,
        i;

    for (i = number.length - 1; i >= 0; i--) {
        sum += sumTable[flip++ & 0x1][parseInt(number.charAt(i), 10)];
    }

    return sum % 10 === 0;
}

// Check if the VISA card input is valid
var regCardNo = (opts.cardData ? /^[0-9]{6}[\*]{6}[0-9]{4}$/ : /^[0-9]{16}$/),
    regMonth = /^[0]{1}[1-9]{1}$|^[1]{1}[0-2]{1}$/,
    regYear = /^[0]{1}[1-9]{1}$|^[1-9]{1}[0-9]{1}$/,
    regCvc = /^[0-9]{3}$/,
    cardNo = cardNumberInput.val(),
    month = monthInput.val(),
    year = yearInput.val(),
    cvc = cvcInput.val();

if(regCardNo.test(cardNo) && regMonth.test(month) && regYear.test(year) && regCvc.test(cvc) && checkCardNumber(cardNo)) {
    payButton.prop("disabled", false);
    return true;
} else {
    payButton.prop("disabled", true);
    return false;
}

All input variables are jQuery elems (they are not defined in this code snippet )

NOTE that the opts.cardData checks if you have a prefilled card number (which gets loaded from the DB), then it checks for a masked number (ex. 123456******1234), else it checks for a full length number which you add in the form your self.

But I guess this is a much better answer, http://stackoverflow.com/questions/72768/how-do-you-detect-credit-card-type-based-on-number — KungWaz, Mar 23 '15 at 16:00

Validate credit card by using jquery

2 Answers2