How to determine if a radio button is checked already

To get the value of the selected radioName item of a form with id myForm:

$('input[name=radioName]:checked', '#myForm').val()

Here's an example:

$('#myForm input').on('change', function() {
   alert($('input[name=radioName]:checked', '#myForm').val()); 
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<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>

This should do it, all of this is in the documentation, which has a very similar example to this:

$("input[type='radio'][name='theme']").click(function() {
    var value = $(this).val();
});

I should also note you have multiple identical IDs in that snippet. This is invalid HTML. Use classes to group set of elements, not IDs, as they should be unique.