if (!this.money)
    {
     console.log('money',money);
     Toast({
      message: '請輸入有效的充值金額',
      duration: 2000
     });
    }

 else if (!this.moneyReal)
    {
     console.log('moneyReal',moneyReal);
     Toast({
      message: '請輸入有效的實付金額',
      duration: 2000
     });
    }

else
    {
     MessageBox.confirm('你確定要充值么?', '提示').then(action => {
     });
    }

<template>
 <div class="app">

  <mt-field label="充值金額" id="money" placeholder="請輸入" v-model="money" type="number"></mt-field>
  <mt-field label="實收金額" id="moneyReal" placeholder="請輸入" v-model="moneyReal" type="number"></mt-field>
  <div class="rechage">
   <button @click="chongZhiForMember">充 值</button>
  </div>
 </div>
</template>

<script>
 import { Field, MessageBox, Toast } from 'mint-ui';
 export default {
  data() {
   return {

    // 會員卡余額
   }
  },
  methods: {

   chongZhiForMember() {
    if(!this.money) {
     console.log('money', money);
     Toast({
      message: '請輸入有效的充值金額',
      duration: 2000
     });
    } else if(!this.moneyReal) {
     console.log('moneyReal', moneyReal);
     Toast({
      message: '請輸入有效的實付金額',
      duration: 2000
     });
    } else {
     MessageBox.confirm('你確定要充值么?', '提示').then(action => {

     });
    }
   }
  },

 }
</script>
<style scoped>
 .app {
  background: #F1F1F1;
  height: 17.78rem;
 }
 
 .rechage button {
  outline: none;
  border: none;
  height: 1rem;
  width: 3.5rem;
  font-size: 0.5rem;
  color: white;
  background: #449EF4;
  border-radius: 0.15rem;
 }
 
 .rechage {
  text-align: center;
  margin-top: 1rem
 }
</style>