利用data对象写倒计时：效果如下图
图计较丑，重点是代码哦》。《
首先，确定要倒计时的终点时间；再利用setInterval动态获取每一刻的时间，然后将获取的时间转换成秒,分，时,日，月
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style>
.block{
width: 200px;
height: 100px;
background-color: #0c0c0e;
color: #fefff3;
}
.shi{
float: left;
margin-left: 4px;
padding-top: 30px;
font-size: 25px;
width: 60px;
height: 70px;
background-color: #000000;
text-align: center;
}
</style>
<script>
window.onload=function(){
var gotime=new Date(2018,8,25,22,00);//设置倒计时终点时间
var b=document.getElementsByClassName ("block")[0];
setInterval(function(){
var nowtime=new Date();//获取当前时间
//下面是将时间差转换成时分秒
var time_c=(gotime.getTime()-nowtime.getTime())/1000;
var shi=parseInt(time_c/(60*60)%24);
var fen=parseInt((time_c/60)%60);
var miao=parseInt(time_c%60);
b.innerHTML="<div class='shi'>"+shi+"时"+"</div>"+"<div class='shi'>"+fen+"分"+"</div>"+"<div class='shi'>"+miao+"秒"+"</div>";
},1)
}
</script>
</head>
<body>
<div class="block"></div>
</body>
</html>