[Dilettante_Pro]

<table>
  <tr>
   <td class="sel">1</td><td>2</td><td class="sel">3</td>
  </tr>
</table>
<script>
   var cells = document.querySelectorAll('.sel');
    for(var i = 0; i < cells.length; i++){
       var d = document.createElement("div");
       d.style = "width:100px;height:100px;background-color: red;";
       cells[i].appendChild(d);
    }
</script>