Subscription - mmmy/css3demos GitHub Wiki
Subscription object is returned by Chart Methods. Using this object you can subscribe to a chart event and unsubscribe from it. So it has two methods:
subscribe(object, method, singleshot)
objectis a context to be used asthispointer formethodfunction. Usenullif you don't need the context.methodis a function to be called when the event happenssingleshotis an optional argument. Set it totrueto be automatically unsubscribed when the event happens first time.
unsubscribe(object, method)
Use the same object and method which you used in subscribe function to unsubscribe from the event.