<html>
<head>
<script language="javascript" type="text/javascript">
function evalGroup(){
var group = document.radioForm.myRadio;
console.log(group.length);
for (var i=0; i<group.length; i++) {
if (group[i].checked)
break;
}
if (i==group.length)
return console.log("No radio button is checked");
console.log("Radio Button " + (i+1) + " is checked.");
}
</script>
</head>
<body>
<form name="radioForm">
Radio Button 1: <input type="radio" name="myRadio" /><br />
Radio Button 2: <input type="radio" name="myRadio" /><br />
Radio Button 3: <input type="radio" name="myRadio" /><br />
Radio Button 4: <input type="radio" name="myRadio" /><br /><br />
<input type="button" value="Eval Group" onclick="evalGroup()" />
</form>
</body>
</html>