如何使用element-ui 限制日期选择

<script src="//unpkg.com/vue/dist/vue.js"></script>

<script src="//unpkg.com/element-ui@2.3.8/lib/index.js"></script>

<p id="app">

<template>

 <p class="block">

  <span class="demonstration">起始日期</span>

  <el-date-picker v-model="startDate" type="date" placeholder="选择日期" :picker-options="pickerOptionsStart" @change="changeEnd">

  </el-date-picker>

 </p>

 <p class="block">

  <span class="demonstration">截止日期</span>

  <el-date-picker v-model="endDate" type="date" placeholder="选择日期" :picker-options="pickerOptionsEnd" @change="changeStart">

  </el-date-picker>

 </p>

</template>

</p>

var Main = {

  data() {

   return {

    pickerOptionsStart: {},

    pickerOptionsEnd:{},

    startDate: '',

    endDate: '',

   };

  },

  methods:{

   changeStart (){

    this.pickerOptionsStart = Object.assign({},this.pickerOptionsStart,{

     disabledDate: (time) => {

      return time.getTime() > this.endDate

     }

    })

   },

   changeEnd (){

    this.pickerOptionsEnd = Object.assign({},this.pickerOptionsEnd,{

     disabledDate: (time) => {

      return time.getTime() < this.startDate

      }

    })

   }

  }

 };

var Ctor = Vue.extend(Main)

new Ctor().$mount('#app')

@import url("//unpkg.com/element-ui@2.3.8/lib/theme-chalk/index.css");

.block{

 margin-top:10px;

}