Getting value from selected radio field using jQuery isn’t tough though. To get the selected radio field value we could use the following code replacing the name radio_input to your desired

<script type="text/javascript">
    var selected_radio_value = $("input[name='radio_input']:checked").val();
</script>

We have used radio name, because not each radio will have the same ID logically. However, it could be also retrieved with class name.

<script type="text/javascript">
    var selected_radio_value = $(".my_radio_input:checked").val();
</script>

To get radio button value when they have changed you can bind on jQuery change event

<script type="text/javascript">
$("input[name='radio_button']").change(function(){
    var selected_radio = $("input[name='radio_input']:checked").val();
    if (selected_radio == 'hello_world'){
        return true;
    }
    else
    {
        return false;
    }
});
</script>

Find some more examples on http://api.jquery.com/radio-selector/ and http://forum.jquery.com/.