Javascript for a popup

Question

What Javascript has to be written for a popup when a link is clicked? Correct me if there is anything else to be done.

Link is written like this.

<div style="float:left; padding-left:9px;"><asp:LinkButton ID="lnkActiveInactive" runat="server" OnClick="lnkActiveInactive_Click" CssClass="linkclass" Font-Underline="True">Cancel My Account</asp:LinkButton></div>

And popup extender is like this.

<cc1:ConfirmButtonExtender DisplayModalPopupID="ModalPopupExtender2" ID="ConfirmButtonExtender2"
                runat="server" TargetControlID="lnkActiveInactive">
            </cc1:ConfirmButtonExtender>
            <cc1:ModalPopupExtender ID="ModalPopupExtender2" OkControlID="btnYesCancel" CancelControlID="btnNoCancel"
                BackgroundCssClass="modalBackground" PopupControlID="pnlCancelPopup" TargetControlID="lnkActiveInactive"
                runat="server">
            </cc1:ModalPopupExtender>

        <asp:Panel CssClass="modalPopup" ID="pnlCancelPopup" runat="server">
                <!-- Common Popup Control Begin -->
                <table class="tblCommonPopup" width="690px" cellpadding="0" cellspacing="0">
                    <tr>
                        <td class="topLeft">
                        </td>
                        <td class="topMiddle">
                        </td>
                        <td class="topRight">
                        </td>
                    </tr>
                    <tr>
                        <td colspan="3" class="middle" align="center">
                            <!-- Content Area Begin -->
                            <table>
                                <tr>
                                    <td>
                                    </td>
                                    <td colspan="2" style="padding-top: 10px;">
                                        <table width="100%">
                                            <tr>
                                                <td align="center">                                             
                                                     Feel free to change your package to Basic, there is no charge for this Package.<br /><br />If you still wish to cancel, 
                                                     your account will become inactive within DealTown and any further billing will <br />discontinue.  
                                                     We will keep you account in our system for some time if you wish to active it again.<br /><br />Are you sure you 
                                                     wish to cancel your account?                                                                                           
                                                </td>
                                            </tr>
                                        </table>
                                    </td>
                                </tr>
                                <tr>
                                    <td align="center" colspan="4">
                                        <input id="btnYesCancel" type="button" value="YES" class="popupButton" />
                                        <input id="btnNoCancel" type="button" value="NO" class="popupButton" />
                                    </td>
                                </tr>
                            </table>
                            <!-- Content Area Ends -->
                        </td>
                    </tr>
                    <tr>
                        <td class="bottomLeft">
                        </td>
                        <td class="bottomMiddle">
                        </td>
                        <td class="bottomRight">
                        </td>
                    </tr>
                </table>
                <!-- Common Popup Control End -->
            </asp:Panel>
        &nbsp;
    </ContentTemplate>
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="imgbtnSubmit" EventName="Click" />
    </Triggers>
</asp:UpdatePanel>