用Ajax来控制书签和回退按钮的代码

p;"Deanna Neuberg ''mom@mom.com''"];

      // cache the address book so it exists
      // even if the user leaves the page and
      // then returns with the back button
      historyStorage.put("addressBook",
                         addressBook);
   }
   else {
      // fetch the cached address book from
      // the history storage
      window.addressBook =
               historyStorage.get("addressBook");
   }


　　处理历史变化的代码是简单的。在下面的代码中，当用户不论按下回退还是前进按钮handleHistoryChange 都被调用。我们得到新的地址(newLocation) 使用他更新我们的用户接口来改变状态，通过使用一个叫displayLocation的O''Reilly Mail的工具方法。

程序代码
** Handles history change events. */
function handleHistoryChange(newLocation,
                             historyData) {
   // if there is no location then display
   // the default, which is the inbox
   if (newLocation == "") {
      newLocation = "section:inbox";
   }

   // extract the section to display from
   // the location change; newLocation will
   // begin with the word "section:"
   newLocation =
         newLocation.replace(/section\:/, "");

   // update the browser to respond to this
   // DHTML history change
   displayLocation(newLocation, historyData);
}

/** Displays the given location in the
    right-hand side content area. */
function displayLocation(newLocation,
                         sectionData) {
   // get the menu element that was selected
   var selectedElement =
            document.getElementById(newLocation);

   // clear out the old selected menu item
   var menu = document.getElementById("menu");
   for (var i = 0; i < menu.childNodes.length;
                                          i++) {
      var currentElement = menu.childNodes[i];
      // see if