Ciao,

<script type="text/javascript">
<!--
function attiva(){
var f = document.mioform;
if(!f.abilita.checked){
document.getElementById("object").style.visibility ='hidden';
}else{
document.getElementById("object").style.visibility ='visible';
}
}
// -->
</script>
</head>
<body>
<form name="mioform">
<input type="checkbox" name="abilita" onclick="attiva()">
</form>

<div id="object" name="object" style="visibility:hidden"><table border="1"><tr><td>TESTO</td></tr></table></div>


Massimo