微信小程序（12）--倒计时

记录一个常见的效果，倒计时。

<text>倒计时：{{content}}</text>

Page({
  /**
   * 页面的初始数据
   */
  data: {
    endTime: '',
    content:''
  },
  /**
   * 生命周期函数--监听页面加载
   */
  onLoad: function (options) {
    var that=this;
    that.setData({
      endTime:''
    })
    that.countdowm();
  },
  countdowm: function (e) {
    let that = this;
    let timer = setInterval(function () {
      let nowTime = new Date();
      let endTime = new Date(that.data.endTime * );
      let t = endTime.getTime() - nowTime.getTime();
      if (t > ) {
        let day = Math.floor(t / );
        let hour = Math.floor((t / ) % );
        let min = Math.floor((t / ) % );
        let sec = Math.floor((t / ) % );
        hour = hour <  ? "" + hour : hour;
        min = min <  ? "" + min : min;
        sec = sec <  ? "" + sec : sec;
        let format = '';
        if (day > ) {
          format = `${day}天${hour}时${min}分${sec}秒`;
        }
        if (day <=  && hour > ) {
          format = `${hour}时${min}分${sec}秒`;
        }
        if (day <=  && hour <= ) {
          format = `${min}分${sec}秒`;
        }
        that.setData({
          content: format
        })
      } else {
        clearInterval(timer);
        that.setData({
          content: '结束了！'
        })
      }
    }, );
  }
})