Help javascript radio button

Javascript - can a radio button options dependent on other radio button choices? My javascript below show no changes  


<script type="text/javascript">

      function setshowName(passvar)
      {
      
             
            if ( passvar == 'T')
            {
                  document.getElementById('showName').value = "yes";
                        }
            else
            {

                  document.getElementById('showName').value = "no";
                  
            }
      
      }
</script>





<form name="testform" method="post">
<table>
  <tr>
      <td>
      Show Address:
        <INPUT TYPE="RADIO" NAME="showaddr" VALUE="A" onclick="setshowName('A')" checked>Show A Address
      <INPUT TYPE="RADIO" NAME="showaddr" VALUE="B" onclick="setshowName('B')">Show B Address
      </td>
  </tr>
  <tr>
      <td>
        Show Test Name:
        <INPUT TYPE="RADIO" NAME="showName" VALUE="yes" checked>yes
        <INPUT TYPE="RADIO" NAME="showName" VALUE="no">no
     </td>
   </tr>
</table>
</form>