<com:TContent ID="Content"> Time : <com:TActiveLabel id="Lbl"/><br/> <com:TActiveButton OnCallback="startBigTask" Text="Start Big Task" ClientSide.HasPriority="false"> <prop:ClientSide.OnLoading> Prado.WebUI.TTimeTriggeredCallback.start('<%= $this->Timer->ClientID %>') </prop:ClientSide.OnLoading> <prop:ClientSide.OnComplete> Prado.WebUI.TTimeTriggeredCallback.stop('<%= $this->Timer->ClientID %>') </prop:ClientSide.OnComplete> </com:TActiveButton> <com:TTimeTriggeredCallback Id="Timer" Interval="0.5" OnCallback="updateLbl" StartTimerOnLoad="false"/> </com:TContent>