How to have only one input selected in a tr?
===

Here's an fiddle example: http://jsfiddle.net/YxU2H/9/
I'm trying to just have one checkbox or one radio button selected in the row. What I've tried doesnt work: 

    function selectedBox() {
          var bothChecked = false;
          var row = $(this).closest('tr');
 
          var isCboxChecked = $('row', '#cbox').is(':checked');
          var isRadChecked = $('row', '#rad').is(':checked');

          //var isCboxChecked = $('#cbox').is(':checked'); //true or false
          //var isRadChecked = $('#rad').is(':checked');

          if (first == second) {
              bothChecked = true;
              //keep checkbox selected but deselect radio button
          }
          if (bothChecked == true) {
              $('#cbox').attr('checked', false);
          }
          else {
              $('#cbox').attr('checked', true);
          }
      } //);


Then I just added an onclick="selectedBox();" to the checkboxes and buttons. Checkboxes had a id of cbox, and radio buttons had rad