比如以下的代码<div class="contentwrap" id="dllastgone">
           <div class="answer_list">
      <div class="asker">xxx</div>      <div class="dline"></div>        <div class="answer_list">
      <p><span>xxx!</span></p>      </div>
      <div class="answer_list">
            <div class="asker">xxx </div>
      <div class="dline"></div>
 
      </div>
我想让id为dllastgone的DIV内的最后一个class="dline"的DIV变为display=none,该如何写呢?