HTML col span 屬性

<table border="1">
  <colgroup>
    <col span="2" style="background-color:red" />
    <col style="background-color:yellow" />
  </colgroup>
  <tr>
    <th>ISBN</th>
    <th>Title</th>
    <th>Price</th>
  </tr>
  <tr>
    <td>3476896</td>
    <td>My first HTML</td>
    <td>$53</td>
  </tr>
</table>