1：DATA中两个变量，
data: {
nav:['头条1','头条2'],
ins:0,//记录当前点击的INDEX
},
2：
<div v-for="(item,index) in nav" :class="index == ins ? 'swiper-slide swiper_active' : 'swiper-slide' " @click="topClick(index)">{{item}}</div>
3：mothods:
topClick:function(i){
var t=this;
t.ins=i;
},