document.observe("dom:loaded", function () {
  
  $$('dd').invoke('hide');
  $$('dd').toArray()[0].show();
  
  $$('dt').each(function (elem) {
    
    elem.observe('click', function () {
      $$('dd').invoke('hide');
      
      $$('dt').each( function (dt_elem) {
        a_elem = dt_elem.down('a');
        a_elem.setAttribute('style', "background-image: url(/static/images/inforightarrow.gif")
      });
      
      elem.next('dd').show();
      class_name = elem.classNames().toArray()[0];
      a_elem = elem.down('a');
      a_elem.setAttribute('style', "background-image: url(/static/images/infodownarrow.gif");
        
    })
  });
  
});