<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>toggle div</title>
<script language="JavaScript" type="text/javascript">
window.onload = init;
function init()
{
document.getElementById('dropper1').style.display = 'block';
document.getElementById('dropper2').style.display = 'none';
}
function toggleDiv(element)
{
var otherId = element == "dropper1" ? "dropper2" : "dropper1";
document.getElementById(otherId).style.display = 'none';
document.getElementById(element).style.display = 'block';
}
</script>
</head>
<body>
<table>
<tr>
<td onClick="toggleDiv('dropper1');">1</td>
<td onClick="toggleDiv('dropper2');">2</td>
</tr>
</table>
<div id="dropper1">
<ul>
<li>1</li>
</ul>
</div>
<div id="dropper2">
<ul>
<li>2</li>
</ul>
</div>
</body>
</html>