window.onload = function () {
     var c = new Vue({
       el : 'body',
       methods : {
        say : function(){
          alert( '欢迎学习vue' );
        }
       }
     });
    }

<input type="button" value="点我" v-on:click="say();"/>

window.onload = function () {
     var c = new Vue({
       el : 'body',
       data : {
         arr : [ 10, 20, 30 ]
       },
       methods : {
        change : function(){
          this.arr.push( 40 );
        }
       }
     });
    }

    <input type="button" value="点我" v-on:dblclick="change();"/>
    <ul id="box">
      <li v-for="value in arr">{{value}}</li>
    </ul>

<style>
    div {
      width: 200px;
      height: 200px;
      background: red;
      float:left;
      margin:20px;
    }
  </style>
  <script src="../js/vue.js"></script>
  <script>
    window.onload = function () {
     var c = new Vue({
       el : 'body',
       
     });
    }
  </script>

 <div v-show="true"></div>
 <div v-show="true"></div>
 <div v-show="false"></div>

<style>
    div {
      width: 200px;
      height: 200px;
      background: red;
    }
  </style>
  <script src="../js/vue.js"></script>
  <script>
    window.onload = function () {
      var c = new Vue({
        el: 'body',
        data: {
          flag: false
        },
        methods : {
          toggle : function(){
            this.flag = !this.flag;
          }
        }
      });
    }

<input type="button" value="点我" v-on:click="toggle();"/>
<div v-show="flag"></div>