vue.js动态操作同级class

<p class="weui-mask" id="guige">
    <p class="guigeBox">
     <p class="guigeTitle">{{guigeName}}</p>
     <p class="guigeP guigeP01">规格</p>
     <p class="indexGuiGe">
      <span v-for="value,index in guigeList" v-on:click="guige(index)" v-bind:class="{on:index==guigeSpan}">{{value.guige_name}}</span>
     </p>
     <p class="guigeP">口味</p>
     <p class="indexKouwie">
      <span v-for="value,index in kouweiList" v-on:click="kouwei(index)" v-bind:class="{on:index==kouweiSpan}">{{value.guige_name}}</span>
     </p>
    </p>
   </p>

var guige=new Vue({
    el: '#guige',
    data:{
     guigeSpan:"-1", //控制点亮状态 -1为默认不点亮
     kouweiSpan:"-1", //控制点亮状态 
    },
   methods:{
     guige:function(index){ //当点击时候点亮，同级的span标签删除Class
      this.guigeSpan = index;
     },
     kouwei:function(index){
      this.kouweiSpan = index;
     },
    }
   })