1, AJAX is most commendable asynchronous interaction, rather than a refresh 

  Many people are not optimistic about AJAX technology refresh, and even agree to do AJAX is not the refresh.    This perception is wrong and what is not refresh?    Refresh page is not without overloading, then what is asynchronous interaction?    Asynchronous interaction is a simple multi-thread, when you see articles in a blog at the same time can be carried out without use of AJAX to refresh the answerer seems, has not updated, but here the most important thing is asynchronous, that is, you can see the side of the article, submitted to the server side you can restore the information, make good use of this asynchronous, can be grasped the essence of AJAX.    Many occasions, no refresh is the user is presented with the visual experience, and it is unknown asynchronous interaction in the work of Taiwan, which led to a wrong interpretation of the majority of the weight of AJAX points. 

  Second, on the recommendation of the WEB lightweight AJAX Application 

  Through the successful application of these two foreign AJAX web site, we found that they are using a lightweight AJAX, this is the one simple interactive, data-less operation.    This also accords with the intention of AJAX, although like www.backbase.com bindows in the RIA and on the performance of astonishing ability, but slow, poor search engine support, development is difficult or impossible to illnesses such as user satisfaction, please remember Accommodation: AJAX ultimate goal is to improve the user experience, in order to facilitate user interaction, and not due to technical and technology. 

  Third, the MVC architecture design AJAX 

  Many people think that in the framework of the application of mature AJAX framework would undermine the integrity of the more common is a three-tier structure of the damage in the MVC WEB application model, in fact otherwise.    MVC theory I do not say more, the classic three-and five-we are familiar with in the WEB application, because the browser / server inherent to such a request / response model off-network communications, a decision in the Model-View can not take the initiative to achieve a data update of the incident, it is generally common framework of the mature MVC MVC classical theory will be some modifications: from Model-processing business after notice Control layer, and then layer by the commitment to the View Control Send obligation to update data.    But AJAX born with monitoring function, AJAX Asynchronous OnReadyStateChange response to the incident that is in the client program will monitor events in function.    Now want to use AJAX realization of the MVC model are as follows Figure this: 

  Idealized design as follows: 

•   The corresponding three-tier document Target: view.jsp (view), action.do (Controller), model.java (model) 
•   View.jsp is that the user interface, and through built-in asynchronous mode AJAX object to the request sent action.do, started listening AJAX.OnReadyStateChange 
•   Action.do view.jsp received the request from the (GET or POST method), through the Request sent to the judge after the corresponding business / data model model.java 
•   Model.java started business operations, and finished view.jsp pages sent directly to the data update notification, the notice may be news of the XML data package, may also be a text, or even a section of the html code, of course, Since using MVC, do not recommend a Model send HTML, XML or a recommendation package business data can be. 
•   View.jsp page AJAX object OnReadyStateChange receive notifications of updates to the data, according to the actual situation with a DOM show pages updated.