vue2.0实现导航菜单切换效果

{ 
 margin:0; 
 padding: 0; 
 } 
 ul li{ 
 list-style: none; 
 } 
 .navul{ 
 margin:100px auto 20px; 
 overflow: hidden; 
 } 
 .navul li{ 
 background-color: #5597b4; 
 padding:18px 30px; 
 float:left; 
 color: #fff; 
 font-size: 18px; 
 cursor: pointer; 
 } 
 .active{ 
 background-color: #5597b4; 
 } 
 .home .home,.new .new,.contact .contact,.service .service{ 
 background-color: skyblue; 
 } 
 .checked{ 
 background: #eff4f7; 
 }

<div id="nav"> 
 <ul> 
  <li v-for="(relation,index) in relations" v-bind:id="relation.id" v-bind:id="relation.id" v-bind:class="{checked:index==nowIndex}" v-on:click="relationClick(index)"> 
  <i></i> 
  <span class="">{{relation.text}}</span> 
  </li> 
 </ul> 
 </div> 

<script src="js/vue.js" charset="utf-8"></script> 
 <script type="text/javascript"> 
 var nav = new Vue({ 
 el:'#nav', 
 data:{ 
 relations: [ 
  {text:'项目',id:'program'}, 
  {text:'人员',id:'person'}, 
  {text:'机构',id:'anization'}, 
  {text:'技术',id:'tech'}, 
  {text:'地区',id:'location'}, 
  {text:'国家',id:'country'} 
 ], 
 nowIndex:-1, 
 }, 
 methods:{ 
 relationClick:function(index){ 
  this.nowIndex=index; 
 } 
 } 
 }); 
 </script>