div.onclick=function(){?console.log(event.currentTarget)?}//這樣點(diǎn)擊后輸出<div?class='out'>..</div> div.onclick=function(){?console.log(event)?}//這樣點(diǎn)擊后輸出事件對(duì)象event，查找該對(duì)象的currentTarget屬性卻為null，明明上一句都可以輸出dom節(jié)點(diǎn)。為何為null？？