var historyCurrentDiv  = "history_content_2011";
    var historyCurrentLi  = "history_item_2011";
    
    function historyInit() {
      var div = document.getElementById(historyCurrentDiv);
      div.style.display = "block";
      
      var li = document.getElementById(historyCurrentLi);
      li.className = "current";
    }
    
    function historySwitchTo(object) {
      var nextDiv  = "history_content_" + object.innerHTML;
      var nextLi  = "history_item_" + object.innerHTML;
      
      var div = document.getElementById(nextDiv);
      div.style.display = "block";

      var li = document.getElementById(nextLi);
      li.className = "current";
      
      div = document.getElementById(historyCurrentDiv);
      div.style.display = "none";

      li = document.getElementById(historyCurrentLi);
      li.className = "";
      
      historyCurrentDiv  = nextDiv;
      historyCurrentLi  = nextLi;
    }