Call Client On Database Change

i am Creating messaging system in asp.net. how can i call client on database change? for example user's开发者_Python百科 Page is open and another user sending message for that user. how can Software notify User ? is it right to call web-service every X seconds/minutes ? any solution with jQuery / AJAX /Comet ? thanks.

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You can take a look at Reverse AJAX

See jQuery Comet Long Poll Implementation

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The AJAX/JQuery solution would be to create a timer polling the web service every X seconds/minutes. Example.

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thanks all answers :).

Comet is a programming technique that enables web servers to send data to the client without having any need for the client to request it. It allows creation of event-driven web applications which are hosted in the browser. http://www.aaronlerch.com/blog/2007/07/08/creating-comet-applications-with-aspnet/