function DayMonthPickerChanged(month, day, days, required) {
    var m = month.val();
    var i = days.size();
    --i;
    var size = 30;

    if (m == 4 || m == 6 || m == 9 || m == 11) {
        size = 29;
    } else if (m == 2) {
        size = 27;
    }

    if (i < size) {
        i = i + (required == true ? 2 : 1);
        for (i; i <= size + 1; ++i) {
            day.append('<option value="' + i + '">' + i + '</option>');
        }
    }
    else if (i > size) {
        if (required == false) {
            ++i;
            ++size;
        }

        for (i; i > size; --i) {
                days.eq(i).remove();
        }
    }
}