微信小程序实现验证码获取倒计时效果

<button disabled='{{disabled}}' data-id="2" bindtap="getVerificationCode">
{{time}}
</button>

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 <= 0) {
 clearInterval(interval)
 that.setData({
 time: '重新发送',
 currentTime:61,
 disabled: false 
 })
 }
 }, 100) 
 },
 getVerificationCode(){
 this.getCode();
 var that = this
 that.setData({
 disabled:true
 })
 },

})