Accurately capturing logout time

xuelun

BACKGROUND INFORMATION

I have a web site which is required to capture a user's login and logout datetime in a database so that the administrator can generate user activity reports anytime.

Right now, it is implemented this way:
1. When the user login successfully, write the new record to the SystemLogs table with the current datetime as the user's login date time.
2. When the user click on a logout button, close session as well as write the current datetime as the user's logout date time to the same record created in step 1 above.

During implementation, it is observed that not all records in the SystemLogs table has the logout datetime filled in (even for users who have obviously already logged out as the date was not the same day). As such, I believe that many users do not click on the logout button.

QUESTION

The problem now is how to capture the logout time when the system's users do not click on the logout button to log out? Is there any way to triger the logout script when user closes the browser window or browse away from the site (out of the same domain name) or any other actions which means that user has left the site?

Look forward to advise from experts out there.

Thank you.

bradgrafelman

You could accomplish this using Javascript and frames.

What you would do is have an intial loading page that simply loads a frame that takes up the entire window, and loads your site's index in the frame. When the window is closed, an 'onunload' event is triggered and will open a page that logs the user out.

If you know any Javascript, you can tweak this script to your liking. Note that on the loading page, you can NOT insert this source inside a <body> tag; it must be either in a <head> tag, or in no tag at all (well, other than <html> of course).

This would be the contents of the loading page:

<script language="JavaScript" for="window" event="onunload">
window.open('http://mysite.com/php/logout.php');
</script>
<frameset border=0 rows="100%,*" noresize>
<frame marginwidth=0 marginheight=0 frameborder=0 framespacing=0 name="TOPFRAME" src="http://mysite.com/php/index.php" 
noresize>
</frameset>

kburger

You could accomplish this using Javascript and frames.

This is assuming javascript is enabled in the browser. You can't rely on that, no more than you can rely on the user to actually "log out".

The only real solution that I can think of is to record the login time in a database and also record a "last activity" time in the database for that user, updated each time they view a page. Then periodically check that database for users that haven't logged out, but whose "last activity" time indicate that they're no longer actively viewing pages. Maybe 30 minutes, an hour -- your choice. Record them as "logged out".