var WindowObjectReference = null; // global variable

function openRadioPopup()
{
  if(WindowObjectReference == null || WindowObjectReference.closed)
  /* if the pointer to the window object in memory does not exist
     or if such pointer exists but the window was closed */

  {
    WindowObjectReference = window.open("http://www.miakatempire.com/page/radio",
           "MKERadioWindowName", "width=250,height=250,resizable=no,scrollbars=no,status=0");
    /* then create it. The new window will be created and
       will be brought on top of any other window. */
  }
  else
  {
    WindowObjectReference.focus();
    /* else the window reference must exist and the window
       is not closed; therefore, we can bring it back on top of any other
       window with the focus() method. There would be no need to re-create
       the window or to reload the referenced resource. */
  };
}