<style type="text/css">
.colockBox
{
width:500px;
height:20px;
color:#000000;
}

.colockBox span
{
float:left;display:block;
width:20px;
height:20px;
line-height:20px;
font-size:18px;
font-weight:bold;
text-align:center;
color:#ffffff;
text-indent:3px;
}

.square
{
float:left;
width:26px;
height:20px;
background-color:#222222;
border-radius:3px;
padding:0px;
margin-right:5px;
}

<script type="text/javascript" src="jquery-1.11.3.js">
<script type="text/javascript">
$(function(){
countDown("2016/12/25 23:00:00","#colockbox1");
});
function countDown(time,id){
var day_elem = $(id).find('.day');
var hour_elem = $(id).find('.hour');
var minute_elem = $(id).find('.minute');
var second_elem = $(id).find('.second');
var end_time = new Date(time).getTime(),//月份是实际月份-1
sys_second = (end_time-new Date().getTime())/1000;
var timer = setInterval(function(){
if (sys_second > 1) {
sys_second -= 1;
var day = Math.floor((sys_second / 3600) / 24);
var hour = Math.floor((sys_second / 3600) % 24);
var minute = Math.floor((sys_second / 60) % 60);
var second = Math.floor(sys_second % 60);
day_elem && $(day_elem).text(day);//计算天
$(hour_elem).text(hour<10?"0"+hour:hour);//计算小时
$(minute_elem).text(minute<10?"0"+minute:minute);//计算分钟
$(second_elem).text(second<10?"0"+second:second);//计算秒杀
} else {
clearInterval(timer);
}
},1000);
}

<div class="colockBox" id="colockBox1">

<div class="square">
<span class="day">00