var _ = [‘00‘, ‘01‘, ‘02‘, ‘03‘, ‘04‘, ‘05‘, ‘06‘, ‘07‘, ‘08‘, ‘09‘], //补零
d = new Date(),
h = d.getHours(),
m = d.getMinutes(),
s = d.getSeconds();
return [_[h] || h, _[m] || m, _[s] || s].join(":");

======

1,this[监听器的对象]
2,event.target[当前目标对象]
<ul onclick="test()">
<li></li>
</ul>

1,你按那里都是:
<ul onclick="test()">
<li></li>
</ul>
2,他可能是ul or li

补零补零