[Javascript] overflow: auto

[Michael_Dougherty at PBP.com (Michael Dougherty)]

<span style='width: 200; height: 300; overflow: auto;'>
  <table>
    <tr>
      <th>Name</th>
      <th>Value</th>
    </tr>
    <tr>
      <td>Row1</td>
      <td>Val1</td>
    </tr>
    (many more rows)
  </table>
</span>

Is there a convenient way to lock the table header so that it doesn't scroll
off the visible area of it's container span?

I would like to not have to define the widths of the columns and have a
fixed table with one row for the header outside the span...