小程序：实现点击倒计时的代码

var interval = null //倒计时函数Page({  data: {    date:'请选择日期',    fun_id:2,    time: '获取验证码', //倒计时     currentTime:61  },   getCode: function (options){    var that = this;    var currentTime = that.data.currentTime    interval = setInterval(function () {      currentTime--;      that.setData({        time: currentTime+'秒'      })      if (currentTime <pre class="brush:js;toolbar:false;"><button>{{time}}</button>