示例：
剩余天数：08天02事02分02秒
html代码：
<div id="timer" data-timer="20160628140203" style="font-size:20px"> ?????剩余天数： ?????<span id="timer_d">0</span>天 ?????<span id="timer_h">0</span>时 ?????<span id="timer_m">0</span>分 ?????<span id="timer_s">0</span>秒 ?</div>
js代码：
timer(‘timer‘);//调用方法 ???????????//时分秒倒计时方法 ?function timer(eleId){ ?????var element=document.getElementById(eleId); ?????if(element){ ?????????endTimer=element.getAttribute(‘data-timer‘); ?????????var endTime=new Date(parseInt(endTimer.substr(0,4), 10),parseInt(endTimer.substr(4,2), 10),parseInt(endTimer.substr(6,2), 10),parseInt(endTimer.substr(8,2), 10),parseInt(endTimer.substr(10,2), 10),parseInt(endTimer.substr(12,2), 10)); ?????????var endTimeMonth=endTime.getMonth()-1; ?????????endTime.setMonth(endTimeMonth); ?????????var ts = endTime - new Date(); ?????????if(ts>0){ ?????????????var dd = parseInt(ts / 1000 / 60 / 60 / 24, 10); ?????????????var hh = parseInt(ts / 1000 / 60 / 60 % 24, 10); ?????????????var mm = parseInt(ts / 1000 / 60 % 60, 10); ?????????????var ss = parseInt(ts / 1000 % 60, 10); ?????????????dd = dd<10?("0" + dd):dd; ??//天 ?????????????hh = hh<10?("0" + hh):hh; ??//时 ?????????????mm = mm<10?("0" + mm):mm; ??//分 ?????????????ss = ss<10?("0" + ss):ss; ??//秒 ?????????????document.getElementById("timer_d").innerHTML=dd; ?????????????document.getElementById("timer_h").innerHTML=hh; ?????????????document.getElementById("timer_m").innerHTML=mm; ?????????????document.getElementById("timer_s").innerHTML=ss; ?????????????setTimeout(function(){timer(eleId);},1000); ?????????}else{ ?????????????document.getElementById("timer_d").innerHTML=0; ?????????????document.getElementById("timer_h").innerHTML=0; ?????????????document.getElementById("timer_m").innerHTML=0; ?????????????document.getElementById("timer_s").innerHTML=0; ?????????} ?????} ?}原文地址：http://blog.csdn.net/xw505501936/article/details/51554835
时分秒倒计时的js实现
原文地址：https://www.cnblogs.com/laq627/p/8472677.html