Answer / alb.shah

Callback : It is a way to send a request to the web page
from the client script. Postback is an expensive call with
processing overhead. In callback a client function sends a
request and a special marked method is invoked on the
server. It does the processing & returns the value which is
received by another client function to process the result.
To have client side callbacks, the page has to implement
ICallbackEventHandler & implement functions
RaiseCallBackEvent & GetCallBackResult.

PostBack: Postback is the event which sends the form data to
the server. The server processes the data & sends it back to
the browser. The page goes through its full life cycle & is
rendered on the browser. It can be triggered by using the
server controls.

Callback is also the form of Postback, but the difference
is in postback execute a complete page life cycle and whole
page redraw, in callback only specific portion (Contorl) is
executed/redraw using client side scriptiong.

I have developed a web application in asp.net 2.0 with Access as back end i am trying to gereate report/export data in excel. After hosting the site i am not getting any error or such exported excel file. but using the source code from my system it works fine. Could any one tell me why it is happening and what is its solution.

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