how to create notificatin in asp website

if you want to follow Old and simple implementation check following code:

setInterval(function() {
  // Call your webmethod here using jquery ajax and refresh notification section
}, 5000);

Let's see some known techniques to refresh current page or some parts of the page upon changes on the server:
Periodic page refresh: This is obviously the worst method since all pages are refreshed. Unfortunately, it is still used on some news portals.

Periodic refreshing of a section in the page: In this method, we make periodic AJAX requests to the server and refresh a part of page with incoming data. This is generally implemented using UpdatePanel and Timer in ASP.NET Web Forms. An improvement to this method can be refreshing the section only if the section data changes. This method is also bad and not scalable since we make the server busy by making periodic requests even when no new data is available on the server. Also, it's not a real time notification since we make requests periodically, not continuously.

Long polling: This is the method that is used by SignalR. We make a request to the server but not receive response until a new data available on the server. Thus, if no new information is available on the server, client and server will just wait, no operation is performed, thus server is not busy

WebSockets: HTML5 comes with websockets API. It allows us to create persistent connections between client and server, thus, server and client can send data to each other asynchronously. It's a higher level TCP connection. This will be the standard way of asynchronous communication on the web in the near future. But, for now, not every browser fully implemented it. As I read but not tried yet, SignalR also has WebSockets support. So, you can use SignalR now and change transport layer in the future.

Hi,

Ref : How to make Notification like facebook