需要使用方法，比如失去焦点，获取其输入值
html
<van-field :value="mes.id_card" placeholder="请输入您得身份证号" :border="false " label="身份证号" @blur='myBlur($event,"id_card")' />
js
myBlur: function (e, name) {
console.log(e)
console.log(name)
if (name === 'name') {
// 姓名
this.mes.name = e.mp.detail.value
} else if (name === 'id_card') {
// 身份证号
this.mes.id_card = e.mp.detail.value
} else if (name === 'description') {
this.mes.description = e.mp.detail.value
}
},
