Indicates which phase of the event flow is currently being evaluated.
var phase = event.eventPhase;
Returns an integer value represented by 4 constants:
Event.NONE = 0
Event.CAPTURING_PHASE = 1
Event.AT_TARGET = 2
Event.BUBBLING_PHASE = 3
The phases are explained in the section 3.1, Event dispatch and DOM event flow, of the DOM Level 3 Events specification.