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Re: [whatwg] Modifying the URL inside beforeunload event

From: Ian Hickson <ian@hixie.ch>
Date: Sat, 15 Nov 2014 02:04:54 +0000 (UTC)
To: cowwoc <cowwoc@bbs.darktech.org>
Message-ID: <alpine.DEB.2.00.1411150200370.7063@ps20323.dreamhostps.com>
Cc: WHATWG <whatwg@whatwg.org>, Michal Zalewski <lcamtuf@coredump.cx>
On Fri, 14 Nov 2014, cowwoc wrote:
> 1. Say we have two pages: OLD and NEW.
> 2. OLD contains a link to NEW.
> 3. I start off on OLD and click on the link.
> 4. The above logic runs ("beforeunload" event handler changes the URL
>    using history.replaceState() from OLD to CHANGED)
> 5. The browser navigates to the NEW page.
> 6. Now... when the user examines the URL associated with the
>    back-button, should he see OLD or CHANGED?

Unless I'm missing something, I'm pretty sure it should be CHANGED. I see 
no reason why it would make a difference whether the replaceState() call 
happens before or during the beforeunload handler; in either case, the 
history traversal hasn't happened yet.

> > Personally the way I build apps these days is to just serve static 
> > files over HTTP, and do all the dynamic stuff over WebSocket, which 
> > would sidestep all these issues.
> You mean you have a single-paged application and rewrite the underlying 
> page asynchronously?

More or less. Google Calendar is an example of the kind of app I mean 
(though obviously that's not one I've written myself!).

> How do you deal with needing to load different Javascript files per 
> page?

You either load it all asynchronously, or you load it on-demand. Depends 
on your precise setup. Generally speaking I find that most of the logic 
ends up on the server; there's just not that much to do purely on the 
client side. Obviously that depends on how sophisticated the app is. If 
it's a game with crazy visuals, there's comparatively more client-side 
code. Similarly, if you have a rich-text editor with offline capabilities, 
there's obviously much more client-side code.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Saturday, 15 November 2014 02:05:24 UTC

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