asp.net 加页面Loading效果

protected void Page_Load( object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                Loading();
            }
        }

        public static void Loading()
        {
HttpContext hc = HttpContext.Current;
            hc.Response.Write("

");
            hc.Response.Write(" ");
            hc.Response.Write("

");
            //hc.Response.Write("");
            hc.Response.Write("");
            hc.Response.Flush();
        }