To get or set property values for client API properties, you must call property accessor methods that are named with the get_ and set_ prefixes. For example, to get or set a value for a property such as cancel, you call the get_cancel or set_cancel methods.
The visibilityMode property determines how a control will behave when the visible property is set to false. Valid values are Sys.UI.VisibilityMode.hide and Sys.UI.VisibilityMode.collapse. The default is Sys.UI.VisibilityMode.hide. For more information, see Sys.UI.VisibilityMode Enumeration.