title: AjaxControlToolkit.ModalPopupExtender not working
body: <p><a href="https://i.stack.imgur.com/6lEuW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6lEuW.png" alt="enter image description here"></a></p>
  
  <p>Im develop the asp.net project,
  Im add the AjaxControlToolkit, but always getting the error. popup is not working,</p>
  
  <pre><code>&lt;asp:ModalPopupExtender ID="mpConfirm" runat="server" CancelControlID="btnDeleteCancel" DropShadow="true"
                      TargetControlID="HiddenField1" PopupControlID="DivConfirm"&gt;
                  &lt;/asp:ModalPopupExtender&gt;
                  &lt;asp:HiddenField ID="HiddenField1" runat="server" /&gt;
                  &lt;div class="panel" runat="server" id="DivConfirm"&gt;
                      &lt;div class="panel-body" style=""&gt;
                          &lt;asp:GridView ID="gvHelp" runat="server" AllowPaging="True" CssClass="table table-bordered table-condensed table-hover" PageSize="5" OnRowCommand="gvHelp_RowCommand" CellPadding="4" ForeColor="#333333" GridLines="None"&gt;
                              &lt;%--&lt;AlternatingRowStyle BackColor="Silver" /&gt;--%&gt;
                              &lt;AlternatingRowStyle BackColor="White" /&gt;
                              &lt;Columns&gt;
                                  &lt;asp:CommandField ShowSelectButton="True"&gt;
                                      &lt;%--&lt;ItemStyle ForeColor="#004080" /&gt;--%&gt;
                                  &lt;/asp:CommandField&gt;
                              &lt;/Columns&gt;
  
                              &lt;%--&lt;HeaderStyle BackColor="#004080" ForeColor="White" /&gt;
                                  &lt;RowStyle ForeColor="Black" /&gt;--%&gt;
                              &lt;EditRowStyle BackColor="#2461BF" /&gt;
                              &lt;FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /&gt;
                              &lt;HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" /&gt;
                              &lt;PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" /&gt;
                              &lt;RowStyle BackColor="#EFF3FB" /&gt;
                              &lt;SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" /&gt;
                              &lt;SortedAscendingCellStyle BackColor="#F5F7FB" /&gt;
                              &lt;SortedAscendingHeaderStyle BackColor="#6D95E1" /&gt;
                              &lt;SortedDescendingCellStyle BackColor="#E9EBEF" /&gt;
                              &lt;SortedDescendingHeaderStyle BackColor="#4870BE" /&gt;
                          &lt;/asp:GridView&gt;
                          &lt;br /&gt;
                          &lt;div&gt;
                              &lt;div&gt;
  
                                  &lt;div&gt;
                                      &lt;asp:Button ID="btnDeleteCancel" Width="55px" Height="25px" runat="server" Text="Cancel" Font-Size="Smaller" CssClass="btn btn-danger btn-xs" /&gt;
                                  &lt;/div&gt;
  
                              &lt;/div&gt;
                          &lt;/div&gt;
                      &lt;/div&gt;
                  &lt;/div&gt;
                  &lt;/div&gt;
  </code></pre>