dhtmlHistory.addListener(handleHistoryChange);
// if we haven't retrieved the address book
// yet, grab it and then cache it into our
// history storage
if (window.addressBook == undefined) {
// Store the address book as a global
// object.
// In a real application we would remotely
// fetch this from a server in the
// background.
window.addressBook =
["Brad Neuberg 'bkn3@columbia.edu'",
"John Doe 'johndoe@example.com'",
"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
