The button visibility extender control's responsibility is to extend a typical button (link, image, or push) into a button that can target another control. In the case of the ButtonVisibilityExtender, it can target some other control and change its visible
status from true to false, or vice versa. This control makes it easy to alter the visible state of another control. Some of the settings are:
IsVisibleInitially - Gets or sets whether the targeted control is visible or hidden.
ReceiverControlID - Gets or sets the ID of the control to target, to change its state. This has to be a control, which the underlying HTML representation has to support the disabled property. This property can be null; if it is, the button is targeted, instead
of the control, not the most desired purpose.