使用Ajax的最大优点，就是能在不更新整个页面的前提下维护数据。这使得Web应用程序更为迅捷地回应用户动作，并避免了在网络上发送那些没有改变过的信息。

-The use of Ajax' s biggest advantage is that we can not update the entire page under the premise of maintaining data. This makes Web applications more rapidly respond to user actions, and avoid the network to send information on those who are not changed.