MessageEvent

The bubbles read-only property of the Event interface indicates whether the event bubbles up through the DOM tree or not.

The cancelable read-only property of the Event interface indicates whether the event can be canceled, and therefore prevented as if the event never happened.

The read-only composed property of the Event interface returns a boolean value which indicates whether or not the event will propagate across the shadow DOM boundary into the standard DOM.

The currentTarget read-only property of the Event interface identifies the element to which the event handler has been attached.

The data read-only property of the MessageEvent interface represents the data sent by the message emitter.

The defaultPrevented read-only property of the Event interface returns a boolean value indicating whether or not the call to Event.preventDefault() canceled the event.

The eventPhase read-only property of the Event interface indicates which phase of the event flow is currently being evaluated.

The isTrusted read-only property of the Event interface is a boolean value that is true when the event was generated by the user agent (including via user actions and programmatic methods such as HTMLElement.focus()), and false when the event was dispatched via EventTarget.dispatchEvent().

The lastEventId read-only property of the MessageEvent interface is a string representing a unique ID for the event.

The origin read-only property of the MessageEvent interface is a string representing the origin of the message emitter.

The ports read-only property of the MessageEvent interface is an array of MessagePort objects containing all MessagePort objects sent with the message, in order.

The source read-only property of the MessageEvent interface is a MessageEventSource (which can be a WindowProxy, MessagePort, or ServiceWorker object) representing the message emitter.

The read-only target property of the Event interface is a reference to the object onto which the event was dispatched.

The timeStamp read-only property of the Event interface returns the time (in milliseconds) at which the event was created.

The composedPath() method of the Event interface returns the event's path which is an array of the objects on which listeners will be invoked.

The preventDefault() method of the Event interface tells the user agent that the event is being explicitly handled, so its default action, such as page scrolling, link navigation, or pasting text, should not be taken.

The stopImmediatePropagation() method of the Event interface prevents other listeners of the same event from being called.

The stopPropagation() method of the Event interface prevents further propagation of the current event in the capturing and bubbling phases.