function showTab(tab_id_base, div_id_base, active_suffix, min_suffix, max_suffix)
{
  for (var i = min_suffix; i <= max_suffix; ++i) {
    var tab_id = tab_id_base + i;
    var tab_element = document.getElementById(tab_id);
if (!tab_element) return; //alert("cannot find tab "+tab_id);
    var div_id = div_id_base + i;
    var div_element = document.getElementById(div_id);
if (!div_element) return; //alert("cannot find div "+div_id);

    if (active_suffix == i) {
      div_element.style.display = "block";
      tab_element.className = tab_element.className.replace(/(?:_active)?$/, "_active");
    } else {
      div_element.style.display = "none";
      tab_element.className = tab_element.className.replace(/(?:_active)?$/, "");
    }
  }
}