<view class="head">

    <navigator class="btn" url="/pages/content/content?id={{chapter_id-1}}"> 上一章 </navigator>

    <navigator class="btn" url="/pages/book_detail/chapter/chapter?id={{novel_id}}"> 目录 </navigator>

    <navigator class="btn"  url="/pages/content/content?id={{chapter_id+1}}"> 下一章 </navigator>

  </view>

如果chapter_id的值是100，减一后传递的参数是99，但是加一后变成1001