How to detect if the session has expired inside the window.onbeforeunload event

[DaveF]

Is anyone using the window.onbeforeunload event to alert the user when they press the back arrow button or refresh the web page? If so, do you have a solution for detecting whether or not their session has expired or if the client is being redirected back to the initial index page?

I don�t want to show an alert when the session has expired. Only when the user does a manual refresh or presses the back button. Unfortunately, the window.onbeforeunload event also fires when the WAS redirects the user back to the index.a5w page. If there was something inside the DOM that I could check to see if the session has expired or the client is being redirected, I could then exit out of the event without showing an alert.

Thanks

[Davidk]

Re: How to detect if the session has expired inside the window.onbeforeunload event

You could set your own session count down timer, set a var and test for that. Here's some very nice code from Stephen and Carole... lots of good stuff in that post.

http://msgboard.alphasoftware.com/al...l=1#post645868

Plus... this would be helpful as well...

<script language="JavaScript">
  window.onbeforeunload = confirmExit;
  function confirmExit()
  {
    if (sessionExpiredVar) {
        exit function
       }
       else
       {
        return "Are you sure you want to exit this page?";
        }
  }
</script>

I haven't tried this yet... just thought I'd throw it out there.

[DaveF]

Re: How to detect if the session has expired inside the window.onbeforeunload event

Thanks David. Your suggestion is very interesting. The code I am binding to the onbeforeunload event is almost identical to your example, but I don't know how or if it's even possible to check to see if the client is being redirected so I can return without displaying an unnecessary message. I think you are suggesting that I setup a timer and do the session timeout myself. And then temporarily override the onbeforeunload event before redirecting the client to the home page. This would be opposed to attempting to react to Alpha redirecting the client to the home page after the session has expired.

[DaveF]

Re: How to detect if the session has expired inside the window.onbeforeunload event

David,

Your suggestion gave me the idea of using the new session timeout warning feature rather than create my own. I wanted to implement this feature anyway. Fortunately, Selwyn included a property called "Confirmation button Javascript" which allows you to enter your own Javascript or just use a special placeholder <ReloadThisPage> which automatically generates the Javascript to reload the page. This property allows me to set a global var (e.g., _SessionExpired) to true so when the window.onbeforeunload event fires, it will immediately return instead of warning the user that they will lose their session.

This is the code I am using for the window.onbeforeunload event:

function ConfirmExit()
{
     if (_SessionExpired)
          return;

     return 'If you continue, you must log back in.';
}

When the app is initialized, I bind ConfirmExit to the window.onbeforeunload event. Every time the user logs in, I initialize _SessionExpired to false. And when the session times out, I set _SessionExpired to true and redirect back to the Login page. If the user reloads the web page or presses the back button after logging in, _SessionExpired is already initialized to false and the confirmation message will appear asking them if they want to proceed.

Thanks again.

[Davidk]

Re: How to detect if the session has expired inside the window.onbeforeunload event

Excellent. I was looking at that property as well since it seemed that you could put your own stuff in there. That's really good... this will be really handy... thanks Dave.