Q:

Best Implement process for Client Callbacks Programmatically without Postbacks in ASP.NET Web Pages

Work on VS2012 C# asp.net web page applicaiton,In the default model for ASP.NET Web pages, the user interacts with a page and clicks a button or performs some other action that results in a postback.  The page and its controls are re-created, the page code runs on the server, and a new version of the page is rendered to the browser.  However, I want to run server code from the client without performing a postback.  If the client script in the page is maintaining some state information (for example, local variable values), posting the page and getting a new copy of it destroys that state.  Additionally, page postbacks introduce processing overhead that can decrease performance and force the user to wait for the page to be processed and re-created. 
To avoid losing client state and not incur the processing overhead of a server roundtrip, I want  to code an ASP.NET Web page so that it can perform client callbacks.  In a client callback, a client-script function sends a request to an ASP.NET Web page.  The Web page runs a modified version of its normal life cycle.  The page is initiated and its controls and other members are created, and then a specially marked method is invoked.  The method performs the processing that you have coded and then returns a value to the browser that can be read by another client script function.  Throughout this process, the page is live in the browser. 
There are several options for automating client callbacks in an ASP.NET Web page.  AJAX features in ASP.NET such as the UpdatePanel server control can automate asynchronous partial-page updates for me, and the Web service communication feature can automate asynchronous Web service calls. 
see the following topics:
1)UpdatePanel Control Overview
2)Microsoft Ajax Overview
3)Partial-Page Rendering Overview
4)ASP.NET AJAX Web Services

Explore ASP.NET AJAX Web Services   
1) Using Web Services in ASP.NET AJAX

2)Exposing Web Services to Client Script

3)Exposing WCF Services to Client Script

4)Calling Web Services from Client Script

I am confused which one is best, please forgive me for lack of my information knowledge ,need help is there anything smart than above.  Is there any smart framework for client callback functionality. 
any type of suggestion will be acceptable,if have any query please ask,Thank in advanced. 

A:

ASP.NET SignalR is perhaps the latest of all the technologies when it comes to achieving real time communication between client and server without full page postbacks.  It is most ideal for a scenario where the data at the server side is expected to change frequently and the same needs to be updated at the client end instantly.  A typical use case for this would be a sports website showing live scores of an ongoing match.  To learn more, refer this link: http://www.asp.net/signalr. 
The technology you choose should depend on your requirements.  If you're using ASP.NET Webforms and developing a site for a niche audience, the AJAX based Update Panel should be able to solve most of your problems.  Then again, there is nothing that the Update Panel can do which plain old JavaScript  (and javascript frameworks like jQuery cannot).  Consumption of web services via JavaScript will always be asynchronous hence not needing page postback.