981574 - onbeforeunload race condition: pressing reload quickly can cause reload despite pressing "Stay on this page"

Status: NEW

(Firefox :: Tabbed Browser, defect)

Description

[Pavel Zavoiskikh]

Attachment: Bug reproduced on jsfiddle.

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.146 Safari/537.36

Steps to reproduce:

1. Setup a site, that is subscribing to onbeforeunload event.

code example:

window.onbeforeunload = function (e) {
    var e = e || window.event;
    //IE & Firefox
    if (e) {
        e.returnValue = 'Your information has not been saved yet. If you leave now, the information might be lost.';
    }
    // For Safari
    return 'Your information has not been saved yet. If you leave now, the information might be lost.';
};

2. Open your website.
3. Hold F5 button (reloads the page repeatedly).
Note: the dialog appears, that is ensuring the user wants to leave the page
4. Press "stay on this page button" repeatedly. (while holding F5 button)
Note: after a while the page starts reloading
5. Press "stay on this page" button one more time.

P.S.
You can find more information about the bug here:
http://stackoverflow.com/questions/22297228/firefox-reloads-page-even-though-i-press-stay-on-this-page-button

You can find swf video file of me reproducing the bug in the attachment. (play it in the browser)

Firefox version: 27.0.1


Actual results:

The page is successfully reloaded.


Expected results:

The page stays as it is.

Comment 1

[[:Aleksej]]

Could you attach here a usable testcase that does not require Flash, please?

Comment 2

[[:Aleksej]]

Never mind: just paste the code from comment #0 into Scratchpad (Shift+F4).

Comment 3

[[:Aleksej]]

(In reply to [:Aleksej] from comment #2)
> Never mind: just paste the code from comment #0 into Scratchpad (Shift+F4).

(on a page whose reloading would be noticable)

Comment 4

[Pavel Zavoiskikh]

(In reply to [:Aleksej] from comment #3)
> (In reply to [:Aleksej] from comment #2)
> > Never mind: just paste the code from comment #0 into Scratchpad (Shift+F4).
> 
> (on a page whose reloading would be noticable)

Did I understand correctly, that you've been able to reproduce this bug and don't need help anymore? If not, I am ready to help, although I didn't quite understand what do you mean by

> Could you attach here a usable testcase that does not require Flash, please?

Flash is not required to reproduce this bug. I've attached a video of me reproducing the bug that requires flash to see it.

Comment 5

[[:Aleksej]]

I can reproduce it, but I had to use Scratchpad to execute the code on an arbitrary page.  At grooveshark.com mentioned at the other page, a Flash warning interfered (at least distracting).

Comment 6

[Pavel Zavoiskikh]

(In reply to [:Aleksej] from comment #5)
> I can reproduce it, but I had to use Scratchpad to execute the code on an
> arbitrary page.  At grooveshark.com mentioned at the other page, a Flash
> warning interfered (at least distracting).

Ok, I got it now. You can also use jsfiddle.net to reproduce this bug. No Flash required there :)

1. Go to jsfiddle.net
2. Type in ANY code in the "javascript" textarea.
3. Hold F5 and press stay on this page repeatedly.
Note: the page is reloaded.

Also! Note that after the page is reloaded you cannot type anything in the text areas.

Comment 7

[Tim Taubert [:ttaubert] (inactive)]

I agree that this is a bug but it seems like a very artificial one to me. How in the world is an average user supposed to hit this? Are there any other *sane* steps to reproduce this?