Know when user accesses/leaves a page

[Todd88]

I know it is extremely easy to know when a user accesses a page. The way I do it is run a query every time a user goes to this certain page. The thing I am having trouble with is finding out when the user leaves.

I have created a chat feature to my website and am trying to get the "users online" based off on who is there at that moment updated by ajax. How do I find out a user has left the page so they are no longer counted among the "users online"? I might be posting in the wrong language forum because this might be javascript/ajax but I'm not sure.... Thanks in advance!

[logic_earth]

Keep track of the last time the user accessed, or updated there session. After a certain amount of time has passed consider the user left.

[Mark Baker]

javascript onunload()or onbeforeunload() might help, but they not well supported, and triggered by a refresh as well as leaving the page

[TomB]

You could keep sending small ajax requests to the server every few seconds. But it's not very nice and a big ol' waste of bandwidth unless you *really* need to know if they've left.

[felgall]

Most scripts just work based on a time period. If the script hasn't heard from them in 5 minutes or 10 minutes the script assumes they've left.

If they are using a browser that supports ajax you could set up the page to signal the server every minute and then if you have previously received a signal and haven't for over a minute then you know they've left.

Doesn't stop them leaving your page open while they go off foe an hour for lunch. Just because the page is still displayed doesn't mean that anyone is looking at it.

[crmalibu]

If you really wanted, you could build upon the suggestions to send an ajax request periodically. This could be combined with additional client side logic which listens for mousemove and keydown events. Going for an extended period of time without either of these events occurring could be used as a pretty decent indication that the user is not actively using the webpage, and has likely walked away/doing something else.

[Todd88]

Yeah I just went with the "being inactive for 10-15 minutes make then go bye bye" code. It was just the simplest way although it doesn't count users who just idle on the page. Thanks for all the suggestions guys.

[felgall]

If you really wanted, you could build upon the suggestions to send an ajax request periodically. This could be combined with additional client side logic which listens for mousemove and keydown events. Going for an extended period of time without either of these events occurring could be used as a pretty decent indication that the user is not actively using the webpage, and has likely walked away/doing something else.

You do need to allow for people who don't have JavaScript/Ajax as well though so you still need a fixed time to use for anyone where the server never receives a signal back from the page.