ISIN validator http://stackoverflow.com/a/16141878

isin-validator.js

function isinValidate(isin) {
    isin = isin.toUpperCase();

    if (!/^[0-9A-Z]{12}$/.test(isin)) {
        return false;
    }

    if (isin.length != 12) return false;
    var v = [];
    for (var i = isin.length - 2; i >= 0; i--) {
        var c = parseInt(isin.charAt(i));
        if (isNaN(c)) { //not a digit
            var letterCode = isin.charCodeAt(i) - 55; //Char ordinal + 9
            v.push(letterCode % 10);
            if (letterCode > 9) {
                v.push(Math.floor(letterCode / 10));
            }
        } else {
            v.push(Number(c));
        }
    }
    var sum = 0;
    var l = v.length;
    for (i = 0; i < l; i++) {
        if (i % 2 == 0) {
            var d = v[i] * 2;
            sum += Math.floor(d / 10);
            sum += d % 10;
        } else {
            sum += v[i];
        }
    }

    return (10 - (sum % 10)) % 10 === Number(isin[isin.length - 1]);
}

var isinArrayValid = [
    "US0378331005",
    "AU0000XVGZA3",
    "GB0002634946"
];

isinArrayValid.map(function (item) {
    console.log(
        "ISIN test correct values: " + isinValidate(item)
    );
});

var isinArrayNonValid = [
    "US0373431005",
    "AU0000GV4TA3",
    "AU0000434ZA3",
    "GB0002634Y46"
];

isinArrayNonValid.map(function (item) {
    console.log(
        "ISIN test non correct values : " + isinValidate(item)
    );
});