Hide Ajax PopupControlExtender on Button click using javascript in Asp.net

Write the javascript function with the name HidePopup():

<script language="javascript" type="text/javascript">

function HidePopup() {

        

         $find('<%=PopupPstureGrip.ClientID%>').hidePopup();

         return false;

     }

</script>

Add Ajax PopupControlExtender control with some properties

<asp:PopupControlExtender ID="PopupPstureGrip"  runat="server" CommitProperty="value"   TargetControlID="txtposture" PopupControlID="PanelPostureGrip" Position="top" ></asp:PopupControlExtender>

Add asp.net Hide Button and call the javascript HidePopup() function in OnClientClick event

<asp:Button ID="btnCancel1" runat="server" Text="Cancel"   OnClientClick="HidePopup();"/>