iran national code javascript validation

national_code.js

// refrence http://www.aliarash.com/article/codemeli/codemeli.htm
function checkNationalCode(code) {
    var L = code.length;

    if (L < 8 || parseInt(code, 10) == 0) return false;
    code = ('0000' + code).substr(L + 4 - 10);
    if (parseInt(code.substr(3, 6), 10) == 0) return false;
    var c = parseInt(code.substr(9, 1), 10);
    var s = 0;
    for (var i = 0; i < 9; i++)
        s += parseInt(code.substr(i, 1), 10) * (10 - i);
    s = s % 11;
    return (s < 2 && c == s) || (s >= 2 && c == (11 - s));
    return true;
}