EventPhase
Represents the different phases of an event.
AtTarget = 2
When an event is dispatched it will be in this
phase on its target attribute value.
Bubbling = 3
When an event is dispatched to an object that
participates in a tree it will be in this phase
after it reaches its target attribute value.
Capturing = 1
When an event is dispatched to an object that
participates in a tree it will be in this phase
before it reaches its target attribute value.
None = 0
Events not currently dispatched are in this phase.