<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>test</title>
<script src="http://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
<form id="qnEditForm">
<input name="mand" type="radio" value="n"/>
<input name="mand" type="radio" value="y" />
</form>
<script>
$(document).ready(function() {
$("#qnEditForm").change(function(){
var mand = $("input[name='mand']:checked").val();
if ( mand == 'y' ){
alert ( mand );
}
});
});
</script>
</body>
</html>