asp.net AJX提供了 Partial-page rendering的技术，比如使用update panel可以轻松的实现这个技术，有时候我们叫做无页面刷新技术，这个技术的好处呢？Partial-page rendering removes the need for the whole page to be refreshed as the result of a postback.By default, postbacks that originate from controls inside the update panel (child controls) automatically initiate asynchronous postbacks and cause a partial-page update.An asynchronous postback behaves much like a synchronous postback.