The EventListener interface is the primary method for
handling events. Users implement the EventListener interface
and register their listener on an EventTarget using the
AddEventListener method. The users should also remove their
EventListener from its EventTarget after they
have completed using the listener.
When a Node is copied using the cloneNode
method the EventListeners attached to the source
Node are not attached to the copied Node. If
the user wishes the same EventListeners to be added to the
newly created copy the user must add them manually.