message: docs(Tabbar): add change event demo
diff: @@ -112,6 +112,31 @@ export default {
  </van-tabbar>
  ```
  +
  +### Change Event
  +
  +```html
  +<van-tabbar
  + v-model="active"
  + @change="onChange"
  +>
  + <van-tabbar-item icon="home-o">Tab1</van-tabbar-item>
  + <van-tabbar-item icon="search">Tab2</van-tabbar-item>
  + <van-tabbar-item icon="freinds-o">Tab3</van-tabbar-item>
  + <van-tabbar-item icon="setting-o">Tab4</van-tabbar-item>
  +</van-tabbar>
  +```
  +
  +```js
  +export default {
  + methods: {
  + onChange(index) {
  + Notify({ type: 'primary', message: index });
  + }
  + }
  +}
  +```
  +
  ### Route Mode
  ```html
  