Menù Jump e php

[dearste]

Ciao a tutti,
ho un form del tipo:

$page_name="showphotos.php";

@$limit=$_GET['limit'];

switch($limit)
{
case 2:
$select2="selected";
$select10="";
$select5="";
break;

case 5:
$select5="selected";
$select10="";
$select2="";
break;

default:

$select10="selected";
$select5="";
$select2="";
break;}

echo "

<form method=get action=$page_name>  
<select name=limit>
<option value=10 $select10>Photos & Info - 10/page</option>
<option value=5 $select5>Photos & Info - 5/page</option>
<option value=2 $select2>Photos & Info - 2/page</option>
</select>
<input type=submit value=GO>
</form>

"; 

vorrei eliminare il pulsante submit e fare un menù jump con javascript, potete aiutarmi??
Grazie, Stefano.