//带天数的倒计时
function countDown(times){
 var timer=null;
 timer=setInterval(function(){
  var day=0,
   hour=0,
   minute=0,
   second=0;//时间默认值
  if(times > 0){
   day = Math.floor(times / (60 * 60 * 24));
   hour = Math.floor(times / (60 * 60)) - (day * 24);
   minute = Math.floor(times / 60) - (day * 24 * 60) - (hour * 60);
   second = Math.floor(times) - (day * 24 * 60 * 60) - (hour * 60 * 60) - (minute * 60);
  }
  if (day <= 9) day = '0' + day;
  if (hour <= 9) hour = '0' + hour;
  if (minute <= 9) minute = '0' + minute;
  if (second <= 9) second = '0' + second;
  //
  console.log(day+"天:"+hour+"小时："+minute+"分钟："+second+"秒");
  times--;
 },1000);
 if(times<=0){
  clearInterval(timer);
 }
}

//单纯分钟和秒倒计时
function resetTime(time){
 var timer=null;
 var t=time;
 var m=0;
 var s=0;
 m=Math.floor(t/60%60);
 m<10&&(m='0'+m);
 s=Math.floor(t%60);
 function countDown(){
  s--;
  s<10&&(s='0'+s);
  if(s.length>=3){
  s=59;
  m="0"+(Number(m)-1);
  }
  if(m.length>=3){
  m='00';
  s='00';
  clearInterval(timer);
  }
  console.log(m+"分钟"+s+"秒");
 }
 timer=setInterval(countDown,1000);
}