Popup reminder before session ends

Hi All,

We have an ASP.Net application v1.1
We have a request that we inform users 5/10mins before session timesout.
The question I have is, how can I implement this on a global level with no/minimum change to existing code?
If I am going in the wrong direction, can someone please tell me how to resolve this issue?

Heres what I have till now:
In .aspx page i have this scritp written
<script language='JavaScript'>
function fncSetTimeout()
{
window.setTimeout('alertUser()',10000);
}
function alertUser()
{
var newWindow = '';
alert('Session is about to expire');
newWindow=window.open('WebForm1.aspx', 'CyberSure','scrollbars=no,resizable=no,width=580,height=500,left=200,top=50, menu=no');
newWindow.opener = self;
}
</script>

on page load I call this script
Dim strTimerScript As String = "<script language='JavaScript'>fncSetTimeout()" + ";<" + "/" + "script>"
Page.RegisterStartupScript("timerScript", strTimerScript)


Thanks in advance
Manju

What is the new window for?

Is the purpose just to inform the user or do you actually want to keep the session alive?

If it's simply to inform the user, then opening up an ASP.NET page as you are doing currently will defeat its own purpose, because it acts as 'browsing to another page', and that will in turn keep the session alive. You should use an HTML page for this if you simply want to inform the user.

Thanks for your response.
The popup is to keep the session alive.

I am wondering if there is a way I can load the javascript globally at some place in the app, so every page will automatically be checked for timeout.

Thanks in advance
Manju

If it's to keep the session alive, then you don't even need the popup. You can do something like this (an invisible image on the page itself)

<img width="1" height="1" src="blankpage.aspx" />

blankpage.aspx is just a normal ASP.NET page, but you can use javascript (set a timer) to keep refreshing the image every minute. This way the requests will go out and because the page gets requested, the session stays alive.