如何解决按钮报错，Component "pages/a/a" does not ha？

VM309:1 Component “pages/a/a” does not have a method “a” to handle event “tap”.

源代码如下：<view class="fl aside">

<view class="aside-item {{item.isActive ? 'active' : ''}}" wx:for="{{asideData}}" wx:key="index" data-active="{{item.isActive}}" data-index="{{index}}" bindtap="a">{{item.title}}</view>