如何防止Bootstrap 4警报在页面加载时显示?

我正在用MVC编写一个应用程序,当用户向订单中添加一个对象时,我会将一条成功消息传递给一个自动解除警报。不过,我已将警报设置为初始隐藏,它仍会在页面加载时显示。

在JS代码段中规定的时间内,该警报仍会在页面加载时显示。

    @if (!string.IsNullOrEmpty(Convert.ToString(Session["UpdResult"])))
    {
        <div id="DivMsg" class="alert alert-success agenda-update">
            @if(Convert.ToString(Session["UpdResult"]).Contains("Err"))
            {
            <div class="alert alert-danger agenda-update text-strong text-center" role="alert" aria-hidden="true">
                <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span>&times;</span></button>
                Sorry, something went wrong. Please
                <a href="#" target="_blank">contact us</a>
                to help with your sessions.
            </div>

            }
            else
            {
            <div class="alert alert-success agenda-update text-strong text-center" role="alert" aria-hidden="true">
                <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span>&times;</span></button>
                @Convert.ToString(Session["UpdResult"])
            </div>                                                
            }
        </div>

    }
    <!-- End Success & Error Messaging -->

Javascript来隐藏警报

@section Scripts {
    <script type="text/javascript">
        window.setTimeout(function () {
            $(".alert").hide();
            $(".alert").fadeTo(500, 0).slideUp(500, function () {
                $(this).remove();
            });
        }, 4000);
    </script>
}