js 错误

Question

  在<asp:ScriptManager ID="ScriptManager1" runat="server">
             </asp:ScriptManager>

   <ContentTemplate>   

          <asp:UpdatePanel ID="UpdatePanel1" runat="server">

           <asp:DropDownList  ID="ddlroom" runat="server" 
                onselectedindexchanged="ddlroom_SelectedIndexChanged">

          </asp:DropDownList>

</ContentTemplate>
             </asp:UpdatePanel>

中的 ddlroom_SelectedIndexChanged 事件使用一下代码            System.Web.HttpContext.Current.Response.Write("<script>window.location=window.location</script>");
总是出错 为什呀