function selectGroup(id) {
   var el = document.getElementById('detailgroup-'+id);
   if (el) {
      var fields = $$('div[id*="detailgroup-"]');
      for(i = 0; i < fields.length; i++) {
         fields[i].style.display='none';
      }   
      el.style.display='block';
   }
}

function initPage() {
   selectGroup(1);
}
Event.observe(document,'dom:loaded',initPage);