function formatNumber(num) {
    var dollarSign = "$";
    if (num < 0) {
        dollarSign = "-" + dollarSign;
        num *= -1;
    }
    return dollarSign + num;
}

function getNumVal(cell) {
    var val = cell.innerHTML;
    if (cell.getElementsByTagName("input")[0] != undefined)
        val = cell.getElementsByTagName("input")[0].value;
    val = cleanValue(val);
    return isNaN(val) ? 0 : new Number(val);
}

function cleanValue(val) {
    retVal = $.trim(val).replace(/\$/g, "");
    return retVal;
}