SOURCE

new Vue({
  el:"#app",
  data(){
    return {
      numValue:'',
      nameValue:'', 
      tipValue:''
    }
  },
  methods:{
    changeNameFun(){
      if(!this.nameValue){
        this.tipValue="姓名不为空"
      }else{
        this.tipValue = this.nameValue;
      }
    },
    changeNumFun(){
      if(!this.numValue){
        this.tipValue="身份证不为空"
      }else{
        this.tipValue = this.numValue;
      }
    }
  }
})

 <div id="app">
      <input
        type="text"
        placeholder="真实姓名"
        v-model="nameValue"
        @blur="changeNameFun"
      />
      <input
        type="text"
        placeholder="身份证号码"
        v-model="numValue"
        @blur="changeNumFun"
      />
      <div>{{tipValue}}</div>
</div>