小程序实现短信登录倒计时

<view class='Form'>
 <form bindsubmit="formSubmit" bindreset="formReset" class='forms'>
  <view class="fidpas">
  <input type="number" class="phonenumber" placeholder="请输入手机号" name="phonenumber" />
  <input type="number" class="message" placeholder="请输入短信验证码" name="msg" />
  <button class="{{sendmsg}}" bindtap="sendmessg" class='btn'>{{getmsg}}</button>
  </view>
  <button class="lgbut" formType="submit" type='warn'>下一步</button>
 </form>
</view>

let timeId = null;
Page({
 data: {
 sendmsg: "sendmsg",
 getmsg: "获取短信验证码",
 },
 sendmessg: function (e) {
 var timer=1;
 if (timer == 1) {
  timer = 0
  var that = this
  var time = 60
  that.setData({
  sendmsg: "sendmsgafter",
  })
  var inter = setInterval(function () {
  that.setData({
   getmsg: time + "s后重新发送",
  })
  time --
  if (time < 0) {
   timer = 1
   clearInterval(inter)
   that.setData({
   sendmsg: "sendmsg",
   getmsg: "获取短信验证码",
   })
  }
  }, 1000)
 }
 }, 
 })

.Form{
 margin-top: 80px;
}
.forms input{
 padding: 10px ;
}
.phonenumber{
 border-bottom: 1px solid #ccc;}
.message{
 display: inline-block
}
.btn{
 display: inline-block;
 font-size: 14px;
}
.forms button{
 margin-top: 15px;
}