var all_lists;

  function history_hide() {
    if(document.getElementsByTagName) {
      all_lists = document.getElementsByTagName("div");

      for(i = 0; i <= all_lists.length-1; i++)
        if(all_lists[i].className == "history")
          all_lists[i].className = "hide";
    }
  }  // ends history_hide()


  function history_show_hide(history_id) {
    var element;

    if(document.getElementById) {
      element = document.getElementById("history_" + history_id);

      if(element.className == "hide")
        element.className = "history";
      else
        element.className = "hide";
    }
  }  // ends history_show_hide().