基本示例:

<from id="app" @submit="checkForm" action="https://##" method="post">
	<p v-if="errors.length">
		<b>Please correct the following error(s):</b>
		<ul>
			<li v-for="error in errors">
				{{error}}
			</li>
		</ul>
	</p>

	<p>
    <label for="name">Name</label>
    <input
      id="name"
      v-model="name"
      type="text"
      name="name">
  </p>
 	<p>
 		<input type="submit" value="提交" />
 	</p>
</form>


<script>
	const app=new Vue({
		el:"#app",
		data:{
			errors:[],
			name:null.
			age:null,
			movie:null
		},
		methods:{
			checkForms:function(e){
				if(this.name && this.age){ return true;}
				 this.errors = [];
     			 if (!this.name) {
      			  this.errors.push('Name required.');
    			  }
     			 if (!this.age) {
      					  this.errors.push('Age required.');
      				}

      e.preventDefault();
			},
			
		},
	});
</script>

另一个自定义校验的例子:

<form
  id="app"
  @submit="checkForm"
  action="https://vuejs.org/"
  method="post"
  novalidate="true"
>

  <p v-if="errors.length">
    <b>Please correct the following error(s):</b>
    <ul>
      <li v-for="error in errors">{{ error }}</li>
    </ul>
  </p>

  <p>
    Given a budget of 100 dollars, indicate how much
    you would spend on the following features for the
    next generation Star Destroyer. Your total must sum up to 100.
  </p>

  <p>
    <input
      v-model.number="weapons"
      type="number"
      name="weapons"
    > Weapons <br/>
    <input
      v-model.number="shields"
      type="number"
      name="shields"
    > Shields <br/>
    <input
      v-model.number="coffee"
      type="number"
      name="coffee"
    > Coffee <br/>
    <input
      v-model.number="ac"
      type="number"
      name="ac"
    > Air Conditioning <br/>
    <input
      v-model.number="mousedroids"
      type="number"
      name="mousedroids"
    > Mouse Droids <br/>
  </p>

  <p>
    Current Total: {{total}}
  </p>

  <p>
    <input
      type="submit"
      value="Submit"
    >
  </p>

</form>

注意顶端的 novalidate="true"。但是这很重要，因为浏览器会尝试在 type="email" 的字段校验邮件地址。坦白说在这个案例中浏览器的校验规则是值得信任的，不过我们想要创建一个自定义校验的例子，所以把它禁用了。

这组输入框覆盖了五个不同的部件。注意这里为 v-model attribute 添加了 .number。它会告诉 Vue 将其值作为数字来使用。

const app = new Vue({
  el: '#app',
  data:{
    errors: [],
    weapons: 0,
    shields: 0,
    coffee: 0,
    ac: 0,
    mousedroids: 0
  },
  computed: {
     total: function () {
       // 必须解析，因为 Vue 会将空值转换为字符串
       return Number(this.weapons) +
         Number(this.shields) +
         Number(this.coffee) +
         Number(this.ac+this.mousedroids);
     }
  },
  methods:{
    checkForm: function (e) {
      this.errors = [];

      if (this.total != 100) {
        this.errors.push('Total must be 100!');
      }

      if (!this.errors.length) {
        return true;
      }

      e.preventDefault();
    }
  }
})

Ajax发送:

const apiUrl = 'https://vuecookbook.netlify.com/.netlify/functions/product-name?name=';

const app = new Vue({
  el: '#app',
  data: {
    errors: [],
    name: ''
  },
  methods:{
    checkForm: function (e) {
      e.preventDefault();

      this.errors = [];

      if (this.name === '') {
        this.errors.push('Product name is required.');
      } else {
        fetch(apiUrl + encodeURIComponent(this.name))
        .then(async res => {
          if (res.status === 204) {
            alert('OK');
          } else if (res.status === 400) {
            let errorResponse = await res.json();
            this.errors.push(errorResponse.error);
          }
        });
      }
    }
  }
})