eventTarget.dispatchEvent(event)

将 event 调度到 event.type 的句柄列表。

• event <Event>
• Returns: <boolean> true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, otherwise false.

Dispatches the event to the list of handlers for event.type.

The registered event listeners is synchronously invoked in the order they were registered.