function formatcurrency(num) {

    num = num.toString().replace(/\$|\,/g,'');

    if (isNaN(num)) {
        num = "0";
    }

    sign = (num == (num = Math.abs(num)));
    num = Math.floor(num * 100 + 0.50000000001);
    cents = num % 100;
    num = Math.floor(num / 100).toString();

    if (cents < 10) {
        cents = "0" + cents;
    }

    for (var i = 0; i < Math.floor((num.length - (1 + i)) / 3); i++) {
        num = num.substring(0, num.length - (4 * i + 3)) +','+ num.substring(num.length - ( 4 * i + 3));
    }

    return (((sign)?'':'-') + num + '.' + cents);

}