<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<-- form input radio
<form id="myForm">
<input type="radio" name="radioName" value="1" /> 1 <br />
<input type="radio" name="radioName" value="2" /> 2 <br />
<input type="radio" name="radioName" value="3" /> 3 <br />
</form>
<script>
$("input[type='radio'][name='radioName']").click(function() {
var value = $(this).val();
});
$('#myForm input [type="radio"][name="radioName"]').on('change', function() {
alert($var value = $(this).val());
});
$("input[name='radioName']:checked").val()
$('#myForm input[type=radio]:checked').val()
$("input[type=radio][name='radioName']:checked").val()
</script>