<view class="button {{className}}">
  <image wx:if="{{src}}" class="button__bg" src="{{src}}" mode="aspectFit" />
  <view class="button__text">
    <text max-lines="{{index}}" overflow="fade">
      <slot></slot>
    </text>
  </view>
  <button class="button__inner" form-type="submit"></button>
</view>