To start with create a new asp.net page and add an instance of the ScriptManager to it. Now configure the ScriptManager to enable calling of page methods marked with WebMethod attribute.
<asp:scriptmanager id="Scriptmanager1" runat="server" enablepagemethods="true" xmlns:asp="#unknown"></asp:scriptmanager>
The next step is to create a web method on the server. The method needs to be marked with the WebMethod attributte.
[WebMethod]
public static void BrowserCloseMethod()
{
HttpContext.Current.Session.Abandon();
}
Finally call the server method on closing the client browser window. Add a javascript method and call this method when the unload event for body of the browser is called.
<script language="javascript" type="text/javascript">
function Browser_Close()
{
PageMethods.BrowserCloseMethod();
}
</script>
<body onunload="Browser_Close()"></body>
