function DateAdd(timeU, byMany, dateObj) {
    var millisecond = 1;
    var second = millisecond * 1000;
    var minute = second * 60;
    var hour = minute * 60;
    var day = hour * 24;
    var year = day * 365;

    var newDate;
    var dVal = dateObj.valueOf();
    switch (timeU) {
        case "ms": newDate = new Date(dVal + millisecond * byMany); break;
        case "s": newDate = new Date(dVal + second * byMany); break;
        case "mi": newDate = new Date(dVal + minute * byMany); break;
        case "h": newDate = new Date(dVal + hour * byMany); break;
        case "d": newDate = new Date(dVal + day * byMany); break;
        case "y": newDate = new Date(dVal + year * byMany); break;
    }
    return newDate;
}