cosi funziona spero vada bene:
codice:
<!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" >
<head>
    <title>Pagina senza titolo</title>
</head>
<body>

<script>
    
</script>

<table border="0" id="tab">
<% for i=1 to 10 %>
        <tr>
        <%for j = 1 to 10%>
            <td><div style='border:1px red solid;width:200px;height:200px'><%=i%>, <%=j %></div></td>
        <% next %>
        </tr>
<% next %>
</table>
<script>document.write('<div style="position: absolute; left: 0px; top: 0px; z-index: 10000;width:'+document.documentElement.scrollWidth+'px; height:'+document.documentElement.scrollHeight+'px;left:0px;top:0px;text-align:center;background-color:Gray;filter: alpha(opacity=75);opacity:0.7;-moz-opacity: 0.75;"></div>')</script>
</body>
</html>