<input type="text" v-model="tel" @focus="inputFocus($event)" @focusout="inputFocusout"/>
export default{
    data(){
        return {
          timer:null,
        }
    },
    methods: {
      inputFocus(){
        clearTimeout(this.timer)
      },
      inputFocusout() {
         this.timer = setTimeout(() => {
            window.scrollTo(0,0)
            // 间隔设为10，减少页面失去焦点定时器的突兀感，
        },10)
      }
    },
    // 用户离开，就只执行销毁监听事件
    destroyed() {
      clearTimeout(this.timer)
    }
}