ciao ragazzi!!!

sto realizzando un semplice sito per presentare la tesina di 5a superiore , ma ho un problema...praticamente vorrei che quando clicco dal menu , la pagina che voglio aprire venga visualizzata nel frame "contenuti" e invece non riesco in quanto si apre una nuova pagina!!!!

frame :

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//IT" "http://www.w3.org/TR/html4/frameset.dtd">

<html>

<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Tesina</title>
</head>

<frameset rows="20%,70%,10%">
<frame src="top.html" name="top" noresize>

<frameset cols="20%,80%">
<frame src="index.html" name="index" noresize scrolling=no>
<frame src="contenuti.html" name="corpo" noresize>
</frameset>

<frame src="footer.html" name="footer" noresize>

</frameset>

</html>

menu :

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="it">

<head>
<title></title>
</head>

<link rel="stylesheet" type="text/css" href="styles.css" />
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript" src="sliding_effect.js"></script>

</head>

<body>

<div id="navigation-block">
[img]background.jpg[/img]
<h2><span>Navigation Effect Using jQuery</span></h2>

<ul id="sliding-navigation">

<li class="sliding-element">RETI
<li class="sliding-element">- Point-to-Point
<li class="sliding-element">- Broadcast

<li class="sliding-element">MEZZI TRASMISSIVI
<li class="sliding-element">- Elettrici
<li class="sliding-element">- Ottici
<li class="sliding-element">- Radio
[/list]
</div>



</body>
</html>