Microsoft JScript runtime error: null is null or not an object

Microsoft JScript runtime error 'null' is null or not an object |

multiHandleSliderTarget.Handle |

MultiHandleSliderExtender | Microsoft JScript runtime error: null is null or not an object

Problem

I have an AJAX MultiHandleSliderExtender Control on the web page and everything work fine. Then I decided to include a Master Page to it, at runtime, I received the client-side error "Microsoft JScript runtime error 'null' is null or not an object".
This is a very weird error, the page work fine without the present of a Master Page. I started to look around and found out that the value of the ID and BehaviorID have to be identical. If you happen to come across the same error, give this solution a try. It work for me.

<cc1:MultiHandleSliderExtender ID="MultiHandleSliderExtender1" runat="server" ShowHandleDragStyle="true"
       BehaviorID="MultiHandleSliderExtender1" TargetControlID="txtSlider" Length="500" ShowInnerRail="true"
            EnableMouseWheel="false" OnClientDrag="Drag" Increment="1" OnClientDragStart="DragStart"
            RaiseChangeOnlyOnMouseUp="true" EnableRailClick="false"
            OnClientDragEnd="DragEnd"
            ShowHandleHoverStyle="true" Maximum="222" Minimum="1">
            <MultiHandleSliderTargets>
             <cc1:MultiHandleSliderTarget ControlID="rangeStart" />
                <cc1:MultiHandleSliderTarget ControlID="rangeEnd" />
            </MultiHandleSliderTargets>  
       </cc1:MultiHandleSliderExtender>