Qualcosa del genere?
codice:
<html>
<head>
<meta http-equiv="content-type" content="text/html;charset=iso-8859-1">
<title>Prova</title>
<style>
<!--
#maintab {position: absolute; top: 0%; left: 0%; width: 100%; height: 100%; visibility: visible}
#lay1 {position: absolute; top: 10%; left: 0%; visibility: hidden}
#lay2 {position: absolute; top: 10%; left: 33%; visibility: hidden}
#lay3 {position: absolute; top: 10%; left: 66%; visibility: hidden}
//-->
</style>
<script language="JavaScript">
<!--
function setVis(id,vis) {
window.document.getElementById(id).style.visibility=vis;
}
//-->
</script>
</head>
<body bgcolor="#ffffff">
<div id="maintab">
<table width="100%" height="100%" border="1">
<tr height="10%">
<td width="33%" onMouseOver="setVis('lay1','visible')" onMouseOut="setVis('lay1','hidden')">link1</td>
<td width="33%" onMouseOver="setVis('lay2','visible')" onMouseOut="setVis('lay2','hidden')">link2</td>
<td width="33%" onMouseOver="setVis('lay3','visible')" onMouseOut="setVis('lay3','hidden')">link3</td>
</tr>
<tr height="90%">
<td width="33%"></td>
<td width="33%"></td>
<td width="33%"></td>
</tr>
</table>
</div>
<div id="lay1" onMouseOver="setVis('lay1','visible')" onMouseOut="setVis('lay1','hidden')">
<table border="1">
<tr>
<td>tabella1</td>
</tr>
</table>
</div>
<div id="lay2" onMouseOver="setVis('lay2','visible')" onMouseOut="setVis('lay2','hidden')">
<table border="1">
<tr>
<td>tabella2</td>
</tr>
</table>
</div>
<div id="lay3" onMouseOver="setVis('lay3','visible')" onMouseOut="setVis('lay3','hidden')">
<table border="1">
<tr>
<td>tabella3</td>
</tr>
</table>
</div>
</body>
</html>