Question

I am setting session time in web config. I also have a javascript for detecting session timeout and letting the user know.

I would like to be able to alert the user 30 sec or a min or more before session timeout with a popup and to give them the opportunity to extend it or cancel and just let it timeout. Can this be done? I have tried to use various methods on the internet but none seem to work. They all require that I download something and I don’t want to have to do that.

<script type="text/javascript">
    var sessionTimeout = "<%= Session.Timeout %>";

    function DisplaySessionTimeout() {
        sessionTimeout = sessionTimeout - 1;

        if (sessionTimeout >= 0)
            window.setTimeout("DisplaySessionTimeout()", 60000);
        else
            alert("Your current Session is over due to inactivity.");
    }
</script>

I am also checking for timeout in code behind and rediecting but thinking about just doing it in javascript.

protected void Page_Init(object sender, EventArgs e)
{
    CheckSession();
}


private void CheckSession()
{
    if (Session["ASP.NET_SessionId"] == null)
    {
       // Session.RemoveAll();
       Response.Redirect("Home.aspx");
    }
}

Answer 1

You have to essentialy have a timer at the same time limit as session; there is no way for the client to know exactly the time the session is at before expiring. That’ what I’ve done in an application.

We do a JQuery $.get("keepalive.aspx") to make a request to an ASP.NET page, which accesses session and refreshes it, keeping the current session alive. You’d also then reset your client-side timer. This has worked well for us.

See this post for more information.