<span v-show="show" @click="getCode">获取验证码</span>
<span v-show="!show" class="count">{{count}} s</span>

 data(){
   return {
    show: true,
    count: '',
    timer: null,
   }
  },
  methods:{
    getCode(){
      const TIME_COUNT = 60;
      if (!this.timer) {
        this.count = TIME_COUNT;
        this.show = false;
        this.timer = setInterval(() => {
        if (this.count > 0 && this.count <= TIME_COUNT) {
          this.count--;
         } else {
          this.show = true;
          clearInterval(this.timer);
          this.timer = null;
         }
        }, 1000)
       }
    }  
  }