With a single control, the id attribute of the popup control uses the unique identifier for the vBMenu it controls, like this:
<td id="MyMENU" class="vbmenu_control"> <a href="#">Single Popup Control</a> <script type="text/javascript"> vbmenu_register("MyMENU"); </script> </td>
<td id="MyMENU.first" class="vbmenu_control"> <a href="#">First Multiple Popup Control</a> <script type="text/javascript"> vbmenu_register("MyMENU.first"); </script> </td> <td id="MyMENU.second" class="vbmenu_control"> <a href="#">Second Multiple Popup Control</a> <script type="text/javascript"> vbmenu_register("MyMENU.second"); </script> </td>