小程序——点击按钮，样式不一样

<view class='shuliang'>

<view class='shuliang_p'>购买数量</view>

<view class='wrap'>

<view class='ping {{amoutIndex==1?"shu":""}}' bindtap='buy' id='1'>30瓶</view>

<view class='ping {{amoutIndex==2?"shu":""}}' bindtap='buy' id='2'>60瓶</view>

<view class='ping {{amoutIndex==3?"shu":""}}' bindtap='buy' id='3'>120瓶</view>

</view>

</view>

---

buy:function(e){

console.log(e.currentTarget.id)

var _this=this;

_this.setData({

amoutIndex: e.currentTarget.id

})

},