How do I warn the user that their web session is about to time out?

I've checked around for a solution but I don't seem to get any directed to asp.net mvc. Basically I'm looking for a solution where a user is notified a minute before the session expires.

The ideal solution wi开发者_Go百科ll be count down notification that will have an option to renew the session.

If the countdown timer expires without the user refreshing the page, I need to log them out.

Something like this:

public class YourController : Controller {
    public ActionResult TheAction() {
        ViewData["SessionTimeout"] = Request.Session.Timout;
        ViewData["SessionWillExpireOn"] = DateTime.Now.AddMinutes(Request.Session.Timeout);
        return View(info);
    }
}

and this:

<span>Your session will expire: <%= ViewData["SessionWillExpireOn"].ToString() %></span>
<span id="countDown" style="display:none></span>
<script type="text/javascript">
    var sessionTimout = <%= ViewData["SessionTimeout"].ToString(); %>;      
    var approximateStart = new Date();
    var notifyAfter = new Date(approximateStart + (sessionTimout - 1)*60*1000);
    function startCountDown() {
        setTimout(function() {
            var now = new Date();
            document.getElementById('countDown').style.display = 'inline';
            document.getElementById('countDown').innerHTML = "Countdown: " + now.getMinutes();
            if (now >= notifyAfter)
                alert('About to expire...');
        }, 5000);
    }
    document.onload=startCountDown;
</script>

Wrote the View in notepad, so please check the syntax. I also don't remember exactly the DateTime stuff in JS.

Anyway you should see the idea.