在createEvent后必须初始化,为大家介绍5种对应的初始化方法
HTMLEvents 和 通用 Events: initEvent( 'type', bubbles, cancelable )...initMouseEvent( 'type', bubbles, cancelable, windowObject, detail, screenX, screenY, clientX, clientY, ctrlKey..., altKey, shiftKey, metaKey, button, relatedTarget )
MutationEvents : initMutationEvent( 'type', bubbles