[Solved] Backspace not working inside KeyUp event of TextBox in jQuery

<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        $("#masterDataFeedDate_Id").on("keyup", function (e) {
            if (e.which == 8) {
                return true;
                e.preventDefault();
            }
            if ($(this).val().length === 4) {
                $(this).val($(this).val() + "-");

            }
            else if ($(this).val().length === 7) {
                $(this).val($(this).val() + "-");
            }
        });
    });
</script>
<div>
    Date :
    <input  type="text" id="masterDataFeedDate_Id" />
</div>