Sys.Application.isCreatingComponents Property
Gets a value that indicates whether the application is in the process of creating components. This member is static and can be invoked without creating an instance of the class.
Note
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.
var isCreating = Sys.Application.get_isCreatingComponents();
Return Value
true if the application is creating components; otherwise, false.