Hello friends,

I am using C# and asp.net to do the following.

When the customer clicks the Transmit Button, I need to have a confirm popup. When the customer presses "Ok", I need to continue with the code behind function. For this I used asp.net ModalPopupExtender. And Created 2 functions in the code behind for "OK" and "Cancel" click events. My aspx code is as follows:

<!-- Panel --> 


<asp:Panel ID="pnlIssues" runat="server" BorderColor="Black" BorderStyle="Outset" BorderWidth="2" BackColor="Wheat" Width="400px" Height="106px">

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

<asp:Button ID="btnWarning" runat="server" Text = "Cancel" OnClick ="RefreshAfterCancel_Click" CausesValidation="false" />
<asp:Button ID="btnOK" runat="server" Text = "OK" OnClick="TransmitAfterOK_Click" CausesValidation="false"/>
</ContentTemplate>
</asp:UpdatePanel> 


</asp:Panel> 


<ajaxToolkit:ModalPopupExtender ID="WarningModal" TargetControlID="dummyLink2" BehaviorID="WarningModal" PopupControlID="pnlIssues" runat="server" ViewStateMode="Enabled" CancelControlID="btnWarning" OkControlID = "btnOK">
</ajaxToolkit:ModalPopupExtender>

<asp:HyperLink ID="dummyLink2" runat="server" NavigateUrl="#" />

This is the code behind:

protected void TransmitButton_Click(object sender, EventArgs e)
{ 
WarningModal.Show();

}

protected void RefreshAfterCancel_Click(object sender, EventArgs e)
{
try
{

Response.Redirect("~/ManageCases.aspx?CaseID=" + GlobalData.CaseID.ToString());

}
catch { }
}

protected void TransmitAfterOK_Click(object sender, EventArgs e)
{

.......}

But when I click the transmit button, it opens the popup and when I click "OK" it gives me the error:

"Microsoft JScript runtime error: Unable to get value of the property 'length': object is null or undefined".

When I click "break" and continue, it does what its supposed to do. I don't understand why it gives the error. This error only shows up in internet explorer. It works fine in FF and Chrome. Also, I am using RADScriptManager in my masterpage.

Any help will be greatly appreciated. I have been trying to figure this out for two days without any luck. I have tried all the tips that were answered for this error message, but still doesn't work for me. Thank you in advance.