EventTarget: dispatchEvent() method

Available in workers

The dispatchEvent() method of the EventTarget sends an Event to the object, (synchronously) invoking the affected event listeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) also apply to events dispatched manually with dispatchEvent().

Calling dispatchEvent() is the last step to firing an event. The event should have already been created and initialized using an Event() constructor.

[!NOTE] When calling this method, the target property is initialized to the current EventTarget.

Unlike “native” events, which the browser fires by queuing a task on the event loop, dispatchEvent() invokes all applicable event handlers synchronously before returning. The read-only isTrusted property is true for native events and false for events dispatched with dispatchEvent().

Syntax

dispatchEvent(event)

Parameters

• event
  • : The Event object to dispatch. Its target property will be set to the current EventTarget.

Return value

false if event is cancelable, and at least one of the event handlers which received event called preventDefault(). Otherwise true.

Exceptions

• InvalidStateError DomException
  • : Thrown if the event’s type was not specified during event initialization.

[!WARNING] Exceptions thrown by event handlers are reported as uncaught exceptions. The event handlers run on a nested callstack; they block the caller until they complete, but exceptions do not propagate to the caller.

Example

See Creating and dispatching events.

Specifications

Browser compatibility

See also

• The Event object reference