function calendar_select_race(calendar_css_id, anchor, container)
{
  new Request.HTML({ url: anchor.href, update: container }).send();
  if(calendar = $(calendar_css_id)) {
    calendar.getElements('td.on').each(function(item) {
      item.removeClass('on');
    });
    if (td = anchor.getParent()) {
      td.addClass('on');
    }
  }
}