
<!-- Paste this code into an external JavaScript file named: simpleSwap.js  -->


    function clrTxt(controlid, textDefault) {
        if (document.getElementById(controlid).value == textDefault) {
            document.getElementById(controlid).value = "";
        }
    }


    function LUNCheck(src, arg) {

        number = arg.Value;

        var i, sum, weight;
        sum = 0;
        for (i = 0; i < number.length - 1; i++) {
            weight = number.substr(number.length - (i + 2), 1) * (2 - (i % 2));
            sum += ((weight < 10) ? weight : (weight - 9));
        }

        if (parseInt(number.substr(number.length - 1)) == ((10 - sum % 10) % 10)) {
            arg.IsValid = true;

        } else {

            //alert("Invalid card number");

            arg.IsValid = false;
        }

    }