codice:
<html>
<head>
	<script language="javascript">
		function controlla_combo()
		{
			document.form1.select.disabled = document.form1.abilita[0].checked;
		}
	</script>
</head>
<body>
	<form name="form1" action="insert.jsp" method=post> 
	<table>
		<tr>
			<td><input type="radio" name="abilita" onclick="controlla_combo();" checked></td>
			<td><input type="radio" name="abilita" onclick="controlla_combo();"></td>
			<td>
				<select name="select" disabled>
					<option value="pippo">pippo</option>
					<option value="pluto">pluto</option>
				</select>
			</td>
		</tr>
	</table>
	</form>
</body>
</html>
ciao