Layer ansprechen

[Homer]

Hallo!

Warum funktioniert das nicht???
...
<script type="text/javascript">
function SubMenue(){
document.layers['Sub1'].bgColor = 'red';
}
</script>

...
<table width="150" height="100%" border="0" cellpadding="0" cellspacing="0" bgcolor="#DFDFDF" class="tabelle">
<tr class="SubMenue1">
<td width="150" height="25" align="left" valign="middle" bgcolor="#D40055" class="con"><a href="#" onClick="SubMenue()">Bathroom Furniture</a>
<div id="Sub1"></div>
</td>
</tr>
</table>
...