Comunque lato cliente....
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled</title>
<script language="JavaScript" type="text/javascript">
<!--
function disable(aDiv) {
var len = aDiv.children.length;
var a = 0;
for (a=0;a<len;a++) {
var curObj = aDiv.children(a);
curObj.disabled = true;
disable(curObj);
} // for (a=0;a<len;a++)
} // function disable(aDiv)
//-->
</script>
</head>
<body>
<div id="contenitore">
<table summary="">
<tr>
<td><input type="text"></td>
</tr>
<tr>
<td>
<select id="myselect" >
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
</td>
</tr>
<tr>
<td><input type="text"></td>
</tr>
</table>
</div>
<script language="JavaScript" type="text/javascript">
<!--
disable(document.getElementById('contenitore'));
//-->
</script>
</body>
</html>