Readonly AT_Readonly BUBBLING_Readonly CAPTURING_Readonly NONEReadonly bubblesReturns true or false depending on how event was initialized. True if event goes through its target's ancestors in reverse tree order, and false otherwise.
Readonly cancelableReturns true or false depending on how event was initialized. Its return value does not always carry meaning, but true can indicate that part of the operation during which event was dispatched, can be canceled by invoking the preventDefault() method.
Readonly composedReturns true or false depending on how event was initialized. True if event invokes listeners past a ShadowRoot node that is the root of its target, and false otherwise.
Readonly currentReturns the object whose event listener's callback is currently being invoked.
Readonly defaultReturns true if preventDefault() was invoked successfully to indicate cancelation, and false otherwise.
Readonly eventReturns the event's phase, which is one of NONE, CAPTURING_PHASE, AT_TARGET, and BUBBLING_PHASE.
Readonly isReturns true if event was dispatched by the user agent, and false otherwise.
Readonly srcReadonly targetReturns the object to which event is dispatched (its target).
Readonly timeReturns the event's timestamp as the number of milliseconds measured relative to the time origin.
Readonly trackReturns the track object (TextTrack, AudioTrack, or VideoTrack) to which the event relates.
Readonly typeReturns the type of event, e.g. "click", "hashchange", or "submit".
Returns the invocation target objects of event's path (objects on which listeners will be invoked), except for any nodes in shadow trees of which the shadow root's mode is "closed" that are not reachable from event's currentTarget.
The TrackEvent interface, part of the HTML DOM specification, is used for events which represent changes to the set of available tracks on an HTML media element; these events are addtrack and removetrack.
MDN Reference