<script src="//unpkg.com/vue/dist/vue.js"></script>
<script src="//unpkg.com/element-ui@2.7.2/lib/index.js"></script>
<div id="app">
<template>
  <!-- `checked` should be true or false -->
  <el-checkbox v-model="checked">Option v-model</el-checkbox>
  <el-checkbox :checked="checked">Option checked</el-checkbox>
  
  {{checked}}
</template>
</div>

@import url("//unpkg.com/element-ui@2.7.2/lib/theme-chalk/index.css");

var Main = {
    data() {
      return {
        checked: true
      };
    }
  };
var Ctor = Vue.extend(Main)
new Ctor().$mount('#app')