经常遇到需要倒计时的地方，下面的JS可以简单实现倒计时，当然可以加上Css使得界面更加美观！
<script type="text/javascript"> function CountDown(){ var EndTime= new Date(document.getElementById('endTime').value);
var NowTime = new Date(); var t =EndTime.getTime() - NowTime.getTime(); var day=Math.floor(t/1000/60/60/24); var hour=Math.floor(t/1000/60/60%24); var min=Math.floor(t/1000/60%60); var sec=Math.floor(t/1000%60); document.getElementById("t_day").innerHTML = day +"Days"; document.getElementById("t_hour").innerHTML = hour + "Hours"; document.getElementById("t_min").innerHTML = min + "Minutes"; document.getElementById("t_sec").innerHTML = sec + "Seconds"; } setInterval(CountDown,1000);</script></head><body> Please select the endTime<input type="datetime-local" id='endTime'><br>
<div> <span id="t_day"></span> <span id="t_hour"></span> <span id="t_min"></span> <span id="t_sec"></span> </div> </body>