Oppure....
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled</title>
<script language="JavaScript" type="text/javascript">
<!--
function scanChecked(aRadioGroup) {
len = aRadioGroup.length;
for (i=0;i<len;i++) {
if (aRadioGroup[i].checked) {
alert (aRadioGroup[i].value);
return aRadioGroup[i].value;
} // if (aRadioGroup[i].checked)
} // for (i=0;i<len;i++)
} // function scanChecked(aRadioGroup)
//-->
</script>
</head>
<body>
1<input type="radio" name="g1" value="1" checked>
2<input type="radio" name="g1" value="2">
3<input type="radio" name="g1" value="3">
4<input type="radio" name="g1" value="4">
5<input type="radio" name="g1" value="5">
6<input type="radio" name="g1" value="6">
7<input type="radio" name="g1" value="7">
8<input type="radio" name="g1" value="8">
9<input type="radio" name="g1" value="9">
10<input type="radio" name="g1" value="10">
11<input type="radio" name="g1" value="11">
12<input type="radio" name="g1" value="12">
<input type="button" value="clicca" onclick="scanChecked(document.getElementsByName('g1'))">
</body>
</html>