layui表格内容溢出的解决方法

 <table class="layui-table">
 <colgroup>
 <col width="100">
 <col width="150">
 <col>
 </colgroup>
 <thead>
 <tr>
  <th>序号</th>
  <th>文章标题</th>
  <th>文章内容</th>
  <th>发布时间</th>
  <th>发布人</th>
  <th>操作</th>
 </tr> 
 </thead>
 <tbody>
 <c:forEach items="${pageInfo.list}" var="a">
 <tr style="height:auto;">
  <td class="lid">${a.aId}</td>
  <td>${a.aTitle }</td>
  <td class="ac" style=""><div style="width:500px;
overflow:hidden; 
white-space:nowrap; 
text-overflow:ellipsis;">${a.aContent}</div></td>
  <td><fmt:formatDate type="both" dateStyle="long" timeStyle="long" value="${a.aTime}" /></td>
  <td>${a.whoRelease}</td> 
  <td>
  <button class="layui-btn-danger layui-btn layui-delete"><i class="layui-icon">&#xe640;</i></button></td> 
 </tr>
 </c:forEach>
 
 </tbody>
</table>