html固定标题列、标题头table(5)

<div class="t_r">
    <div class="t_r_t" id="t_r_t">
        <div class="t_r_title">
            <table>
             <tr>
               <th width="10%">字段A</th>
               <th width="20%">字段B</th>
               <th width="10%">字段C</th>
               <th width="20%">字段D</th>
               <th width="20%">字段E</th>
               <th width="20%">字段F</th>
             </tr>
            </table>
        </div>
    </div>
  <div class="t_r_content" id="t_r_content" onscroll="aa()">
      <table>
        <tr>
          <td width="10%" class="bordertop">1</td>
          <td width="20%" class="bordertop">1</td>
          <td width="10%" class="bordertop">1</td>