Mine

<html>
<head>
 <Title>menù con cartelle</Title>
<style>
DIV.clTop{
	position:absolute;
	width:250px;
	height: 65px;
}
DIV.clSub{
	position:absolute;
	left:15px;
	top:25px;
	width:250px;
	height: 35px;
}
#divCont{position:relative; left:10px; top:0px; height:300px; width:250px;}
A.clMain{font-family:VERDANA; font-size:11px; text-decoration:none; font-weight:bold; color:#000000}
A.clSubb{font-family:Verdana, Arial, Helvetica, sans-serif; font-size:11px; text-decoration:none; color:#000000}
#divMain{position:absolute}
A:link, A:visited { text-decoration: none }
A:hover { text-decoration: none; color:#D76B00}
</style>
	<style type="text/css">
		
		.menu  {display:none; margin-left:20px}
	
	.Stile1 {
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 16px;
}
	.Stile2 {
	font-family: Verdana, Arial, Helvetica, sans-serif;
	font-size: 12px;
}
    </style>

 
 <script type="text/javascript" language="Javascript">
		<!--

		function mostraMenu(menuCorrente) {
			if (document.getElementById) {
				questoMenu = document.getElementById(menuCorrente).style
				if (questoMenu.display == "block") {
					questoMenu.display = "none"
				}
				else {
					questoMenu.display = "block"
				}
				return false
			}
			else {
				return true
			}
		}

 -->
	</script>
	<!-- Fine Sezione JavaScript -->

 
</head>

<body>
 
 <?php
 require('connetti.php');
 
$query="SELECT gruppi.gruppo,campi.id,campi.campo FROM `gruppi` Join campi  where  gruppi.id=campi.id_gruppo";
//$query="SELECT * from gruppi";
 $res=mysql_query($query,$db);
 $id_camp='id';
 $i=0;
 
 while($row=mysql_fetch_array($res)){	

 $arr[$row['gruppo']][$row['id']]=$row['campo'];
 }
 foreach($arr as $k=>$v){ 
 echo $k;
 
 foreach($v as $campo){ 
 
 echo  $campo;
 
 
 ?>

 
<h3><a href="#" onClick="return mostraMenu('menu<?=$i;?>')"><span class="Stile1"><?php echo $k?></span></a></h3>

<?php  ?>

<div class="menu" id="menu<?=$i;?>">
	<a href="caratteristiche.php?id_cat=<?=$row[$id_camp];?>" class="Stile2"><?php echo $campo;?> </a> 
 </div>



<?  $i++;} }?>
</body>
</html>