Confirmation Message Box Value is Null

Hi ,

I am binding some data to the DataGrid , DataGrid is Inside Update Panel.

I have one DropDownList that is also inside UpdatePanel.When I clicking the DropDownList I am showing confirmation Box Yes/No.

But when I click Yes , I am not able to get Value Yes in Hiden Filed.

 function Confirm(sender) {

            var selectedText = $(sender).find("option:selected").text();
            if (confirm("Do you want to change status to " + selectedText + " ?")) {$("#hfResponse").val('Yes');$(hfColorStatus).val(selectedText);
            } else {$("#hfResponse").val('No');
            }


        }



<asp:UpdatePanel ID="uppnlDatgrid" runat="server"><ContentTemplate><asp:DataGrid ID="dgrd" AllowPaging="false" OnItemDataBound="dgrd_OnItemDataBound"
                OnItemCreated="pnlDA_dgrdCSUB_OnItemCreatedEventHandler"
                 AllowSorting="True" AutoGenerateColumns="False"

                ShowHeader="true" ShowFooter="true" " CssClass="font"
                DataKeyField="p_id" Visible="true" Width="100%" runat="server" CausesValidation="false"><Columns><asp:TemplateColumn HeaderText="No" ItemStyle-Width="2%" ItemStyle-HorizontalAlign="Left" HeaderStyle-HorizontalAlign="Left"><ItemTemplate><%#  Container.ItemIndex + 1%></ItemTemplate></asp:TemplateColumn><asp:TemplateColumn ItemStyle-Width="15%" HeaderText="Status"><ItemTemplate><asp:UpdatePanel ID="UpdatePanelColorStatus" runat="server"><ContentTemplate><asp:DropDownList ID="ddlColorStatus" runat="server" OnSelectedIndexChanged="ddlColorStatus_SelectedIndexChanged" AutoPostBack="true"><asp:ListItem Text="Please Select" Value="Please Select"></asp:ListItem><asp:ListItem Text="Green" Value="Green"></asp:ListItem><asp:ListItem Text="Amber" Value="Amber"></asp:ListItem><asp:ListItem Text="Red" Value="Red"></asp:ListItem></asp:DropDownList></ContentTemplate></asp:UpdatePanel></ItemTemplate></asp:TemplateColumn></Columns></asp:DataGrid></ContentTemplate></asp:UpdatePanel><asp:HiddenField ID="hfResponse" runat="server"  />




   protected void ddlColorStatus_SelectedIndexChanged(object sender, EventArgs e)
    {
        string _Status;
        DropDownList chk1 = (DropDownList)sender;
        _Status = ((System.Web.UI.WebControls.ListControl)(chk1)).SelectedValue;


        chk1.Attributes.Add("onchange", "return Confirm(this)"); string confirmValue = hfResponse.Value;
        //ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "alert", "Confirm(this); ", true);

        if(confirmValue =="Yes")
         {

         }


    }