如何在IE中设置表格单元格的div 100%高度

<table>
  <tr>
    <td>
      <div id="myDiv"></div>
    </td>
  </tr>
</table>

table {
  width: 100%;
  height: 100%;
}

td {
  padding: 0;
}

#myDiv {
  height: 100%;
  background-color: #ccc;
}

window.onload = function() {
  var table = document.getElementsByTagName('table')[0];
  var td = table.getElementsByTagName('td')[0];
  var div = td.getElementsByTagName('div')[0];
  div.style.height = td.offsetHeight + 'px';
};