详解小程序毫秒级倒计时（适用于拼团秒杀功能

Page({
 
 /
   页面的初始数据
  /
 data: {
  countdown:''
,  endDate2: '2018-08-08 11:41:00'
 },
 /
   生命周期函数--监听页面加载
  /
 onLoad: function (options) {
  var that = this;
  that.countTime()
 },
 countTime() {
  var that = this;
  var date = new Date();
  var now = date.getTime();
  var endDate = new Date(that.data.endDate2);//设置截止时间
  var end = endDate.getTime();
  var leftTime = end - now; //时间差               
  var d, h, m, s, ms;
  if (leftTime >= 0) {
   d = Math.floor(leftTime / 1000 / 60 / 60 / 24);
   h = Math.floor(leftTime / 1000 / 60 / 60 % 24);
   m = Math.floor(leftTime / 1000 / 60 % 60);
   s = Math.floor(leftTime / 1000 % 60);
   ms = Math.floor(leftTime % 1000);
   ms = ms < 100 ? "0" + ms : ms
   s = s < 10 ? "0" + s : s
   m = m < 10 ? "0" + m : m
   h = h < 10 ? "0" + h : h
   that.setData({
    countdown: d + "" + h + "" + m + "" + s + ":" + ms,
   })
   //递归每秒调用countTime方法，显示动态时间效果
  setTimeout(that.countTime, 100);
  } else {
   console.log('已截止')
   that.setData({
    countdown:'00:00:00'
   })
  }
  
 },
})

<view>
  <text>{{countdown}}</text>
</view>