[Dilettante_Pro]

<table border="1" id="row">
  <tr>
    <td width="20" height="20"></td>
    <td width="20" height="20"></td>
    <td width="20" height="20">2</td>
    <td width="20" height="20"></td>
</tr>
</table>
<script>
window.onload = function () {
   arr= document.getElementById("row").getElementsByTagName("td");
   colors= "red";

	for (var i=0; i!= arr.length; ++i) {
		if (typeof arr[i] !== "" && arr[i].innerHTML != "") {
			arr[i].style.background=colors;
		}	
	}
}

</script>