ho riprovato ad adattare la mia pagina a quella delle faux columns. Il problema non si risolve, resta cmq per Firefox:

ecco il codice utilizzato sulla base delle FC:
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Layout Liquido a tre colonne percentuali</title>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1">
<meta name="generator" content="HAPedit 3.1">
<style type="text/css" media="screen, projection">
html,body{margin: 0 auto;padding: 0; width:90%}
body{font: 76% Verdana,Arial,sans-serif}
h1,h2,h3{font-family: "Trebuchet MS",Arial,sans-serif;margin: 0}
h1{color: #7FA0B1;font-size: 200%}
h2{color: #B8B8B8;font-size: 180%}
h3{color: #A47E6A;font-size: 150%}
p{margin: 0 0 0.8em 0; text-align:justify; }

div#container{min-width: 550px;background: #FFF url(leftP.gif) repeat-y 25%}
div#container2{background:  url(rightP.gif) repeat-y 75%}
div#header{height:auto;line-height: auto;    background: #fff; text-align:center;}
div#rigasup{ height: 12px; line-height:12px; background:#0000CC; border: 1px solid #000; }


div#nav,div#extra{width:20%;\width:22%;w\idth:20%;padding: 0 1%}
div#nav{float:left; margin-top: 10px; height:200px; font-size: large}
div#extra{float:right; font-size:9px;}

div#content{margin: 0 16%}
div#content p{line-height:1.3}

div#rigainf{ height: 12px; line-height:12px; background:#FF0000; border: 1px solid #000; }

div#footer{clear:both; background: #fff url(footer.jpg) repeat-x top;color: #4E768A}
div#footer p{margin: 0;padding: 10px 0;text-align: center;font-size: 80%}

div#nav a, div#nav a:link, div#nav a:visited {
	display:block;
	text-decoration:none;
	padding-left: 5px;
	color: #009;
}

div#nav a:hover, div#nav a:active {
	background-color: #FBA29F;
	border-right-style: solid;
	border-right-color: #2B5B81;
	border-right-width: 5px;
} /* colori per l'effetto roll-over */
</style>
<!--[if lte IE 6]>
<style type="text/css" media="screen, projection">
div#container{ width: expression(document.body.clientWidth<=550 ? "550px" : "auto")}
div#content{height:1%}  /*risolve il peekaboo bug e il 3 pixel jog*/
</style>
<![endif]-->
<style type="text/css" media="print">
body{font: 12pt Arial,sans-serif}
h1,h2,h3{font-family: "Trebuchet MS",Arial,sans-serif}
h1{font-size: 160%}
h2{font-size: 140%}
h3{font-size: 120%}
p{line-height: 1.2}
div#header{border-bottom: 1px solid #000}
div#nav,div#extra, a#skipnav{display:none}
div#footer{border-top: 1px solid #000;font-size: 80%}
</style>

<script type="text/javascript">
<!--
function showhide( targetId ){
if (document.getElementById){
target = document.getElementById( targetId );
 if (target.style.display == "none"){
  target.style.display = "block";
 } else {
  target.style.display = "none";
 
 }
}
}
// -->
</script>
</head>
<body>
<div id="container">
<div id="container2">
    <div id="header">
        <h1>[img]logo3.jpg[/img]</h1>
		<div id="rigasup"></div>
    </div>
    <div id="nav">
       Chi siamo

			Attivit&agrave;

			News

			Scheda Enti

			Contatti

    </div>
<div id="extra">
 testo
    </div>
    <div id="content">
        <a name="startcontent" id="startcontent"></a>
        <table width="100%"  border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td valign="top">
<p class="rilievo">testo/p>
<p class="mostra">Continua</p>
<table width="100%" cellpadding="0" cellspacing="0">
          <tr>

          </tr>
          <tr>
            <td height="2" id="1" style="display:none" >

					  <table border="0" cellpadding="0" cellspacing="0">
                      <tr>
                        <td><p class="testo2">testo 
</p></td>
                    </table>
            </td>
          </tr>
</table>
</td>
  </tr>
</table>
    </div>

    <div id="footer">
				<div id="rigainf"></div>
        

© 1997-2004 - Grafica, layout e guide sono di esclusiva proprietý di HTML.it s.r.l.

        Note e informazioni legali</p>

    </div>
</div>
</div>
</body>
</html>