c# - Session Timeout Warning in ASP.NET

Question

I have an asp.net site that I need to have a popup/layer/alert happen when the session reaches its timeout (lets say 10 minutes). The popup will say that your account session will exprire due to inactivity and have a button for continue session or a button for logout.

I see different ways to do this online, but what's the best/proper way to handle this? Do I have to put an additional timeout if the popup is open too long?

Answer 1

<script type="text/javascript">
    var sessionTimeoutWarning = "<%= System.Configuration.ConfigurationManager.AppSettings["SessionWarning"].ToString()%>";
        var sessionTimeout = "<%= Session.Timeout %>";

    var sTimeout = parseInt(sessionTimeoutWarning) * 60 * 1000;
    setTimeout('SessionWarning()', sTimeout);

    function SessionWarning() {
        var message = "Your session will expire in another " +
            (parseInt(sessionTimeout) - parseInt(sessionTimeoutWarning)) +
            " mins! Please Save the data before the session expires";
        alert(message);
    }
</script>