Radio Button

HTML

<input type="radio" name="foo" id="first">
<input type="radio" name="foo" checked="checked">
<input type="radio" name="foo">
<br>
<span id="event">No events yet.</span>

JavaScript

$(function() {
    $('input[type=radio][name=foo]').change(function(e) {
        if (this.id == 'first') {
            $('#event').text("First radio checked");
        } else {
            $('#event').text("First radio unchecked");
        }
      });
});