[whatwg] When closing the browser

Ian Hickson ian at hixie.ch
Thu Jun 4 17:02:05 PDT 2009

On Mon, 27 Apr 2009, Tab Atkins Jr. wrote:
> On Mon, Apr 27, 2009 at 1:24 PM, Ian Hickson <ian at hixie.ch> wrote:
> > One option would be to have an attribute, say <body logout="">, which
> > causes the user agent to ping the site when the window is closed and there
> > are no other windows open to the same origin.
> >
> > Of course this would break if the other window in question was open to a
> > different page that didn't have the logout="" attribute..
> >
> > Maybe it should be invoked if there are no other pages open that have the
> > same logout="" attribute?
> >
> > This has the advantage of not depending on JavaScript, and not affecting
> > the browser's performance (no waiting for sync XHR, etc).
> >
> > It would work somewhat like PING does today, though probably using POST.
> As an author, I'd definitely use it.  I'd want the second option (ping 
> when you close the last window with a given logout attribute), as that 
> would allow me to define 'domains' within the same origin that track 
> logins separately.
> It would be easy to code against the lack of this (just do an occasional 
> cleanup of sessions that have aged too much, which you'd have to do 
> anyway in case of nonstandard browser exits), but would allow better, 
> more reliable security for users with browsers that implement it.
> Trying to handle this through javascript onunload is nontrivial 
> currently, but @logout would make it both trivial and dependable.

On Mon, 27 Apr 2009, João Eiras wrote:
> What if there is a loss of connectivity or the user agent crashes ? 
> Relying on user agent telling when documents are unloaded has never been 
> reliable nor will ever be. So, websites do timeouts and will continue to 
> do so because those are needed.
> This is really about making the whole logout process more friendly for 
> the web developer though. I thought of exporting a service, using a 
> special element or something, which the user agent could call when if 
> unloads all documents related to that origin or a special token in that 
> element. Like <logout specialtoken="123abcsessionid" content="/logout">
> The user agent would do a GET request of /logout when it no longer had 
> documents loaded on windows with a logout tag with that specific 
> specialtoken value. specialtoken (or whaever you'd like to call it) 
> could be optional and in that case the user agent could rely on origin.
> This way, the server would not need to count the number of loaded 
> documents.

On Mon, 27 Apr 2009, Philipp Kempgen wrote:
> Maybe <link rel="logout" href="..."> is more suitable?
> Server-side applications should probably implement that in a way such 
> that just one session (identified by a session cookie or whatever) gets 
> logged out -- in contrast to all sessions of a user. The user might be 
> logged in using 2 different browsers and might want to log out in one 
> browser but keep the session active in the second one.
> And I'd probably want a same domain policy for the logout ping be 
> implemented in the browser.

On Tue, 28 Apr 2009, Bil Corry wrote:
> I like the idea -- thinking out loud here, rather than invoking it when 
> all pages having the same logout="" attribute are closed, can it instead 
> use some other grouping identifier?  That would allow a developer to 
> pass back unique information from each page via the URI.  And I like 
> POST instead of GET.  A same-origin restriction would be good too.  
> Would the browser accept a response from the logout?  I'm thinking that 
> could be used to immediate end the cookie(s).

I like Philipp's idea of making this a new "rel" value. I encourage people 
who are interested in this idea to add it to the WHATWG RelExtensions 
wiki, write a spec for it (you can put it on a page on that wiki if you 
like) and then see if browser vendors are interested in supporting this 

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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