Programmatically show hide AJAX "PopupControlExtender"

in aspx page

<asp:Panel ID="divPopup" runat="server" CssClass="DivPopup"></asp:Panel>

<ajaxToolkit:PopupControlExtender ID="PopupExtndr" runat="server" PopupControlID="divPopup" TargetControlID="fakeButton" BehaviorID="popupBhvr">

use following javascript syntax to show hide PopupControlExtender:

$find('popupBhvrPopupBehavior').hide();

$find('popupBhvr').showPopup();