[drupal-devel] [feature] Prevent accidentally navigating away from pages where content has changed

Mon Sep 12 21:53:04 UTC 2005

Issue status update for 
http://drupal.org/node/30220
Post a follow up: 
http://drupal.org/project/comments/add/30220

 Project:      Drupal
 Version:      cvs
 Component:    base system
 Category:     feature requests
 Priority:     normal
 Assigned to:  Anonymous
 Reported by:  m3avrck
 Updated by:   Dries
 Status:       patch (code needs review)

I want some JS-folks to review the code.

Dries

Previous comments:
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Thu, 01 Sep 2005 22:47:42 +0000 : m3avrck

How many times have you been posting a comment or working on a new post
when you click on a link in another application and you navigate away
from the content you are editing, losing all of your changes?

Well I say we introduce a script, much similiar to that of Blogger,
that uses the Javascript window.onbeforeunload handler to prevent this
from happening. We can set this handler to call a function that
compares the contents of all forms when the page loads and then quickly
compares that to the current contents just before the user is about to
leave the page. If they have changed, we should prompt the user so they
don't lose their work. This would save many headaches and degrade nicely
for users without Javascript.

Additionally, this script should work with the newly introduced
JS-based upload feature to prevent navigating away as a file is being
uploaded as well.

If I have sometime I'll start work on a patch tomorrow, just wanted to
get the idea into the queue right now :)

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Sat, 10 Sep 2005 23:48:33 +0000 : StuartDH

Sounds like a great feature to me. We regularly get authors and editors
telling us that they've lost the last hour of work by accidentally
navigating away, and I've even just had one of them email me about it a
few minutes ago, so it'd be great if you could put something together
for this.

Cheers

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Mon, 12 Sep 2005 14:33:58 +0000 : MichelleC

Sounds great to me, too. I often have several tabs open doing stuff and
it's easy to lose my place and leave a page with unfinished edits.
Would this alert you when you're going to close an unsaved tab/window
as well?

Michelle

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Mon, 12 Sep 2005 14:34:19 +0000 : MrMattles

Great for us multitaskers that rush and click the wrong thing

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Mon, 12 Sep 2005 14:36:52 +0000 : chx

Very strong -1 as this is IE only.

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Mon, 12 Sep 2005 14:38:40 +0000 : praseodymium

Konqueror already does this, +1 for the idea in general.

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Mon, 12 Sep 2005 15:07:21 +0000 : webchick

Yeah, I think chx is correc that onbeforeunload is an extension
developed by MS [1] (it's not in the ECMAScript specification [2].
However, I found out that this is implemented in Mozilla since 1.7 [3]
(which corresponds to Firefox 1.0, I think?) and I've tested
Blogger.com's version of this functionality in:

Firefox 1.0.6 (working)
Firefox Deer Park Alpha 1 (working)
Opera 8.0.2 (working)
Safari 1.3 (does NOT work)
Safari 2.0.1 (working)

So it seems to be a 'de facto' standard if nothing else.
[1]
http://msdn.microsoft.com/workshop/author/dhtml/reference/events/onbeforeunload.asp
[2]
http://www.ecma-international.org/publications/standards/Ecma-262.htm
[3] http://www.mozilla.org/status/2004-03-01.html

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Mon, 12 Sep 2005 15:09:15 +0000 : webchick

Also, I should clarify... that "does NOT work" in Safari doesn't display
any errors or anything, it just doesn't save the form results as
expected (so pre-Tiger Safari users are going to be used to this). So I
don't see any harm in including this functionality since it seems to
degrade gracefully in non-supporting browsers.

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Mon, 12 Sep 2005 21:10:18 +0000 : m3avrck

Attachment: http://drupal.org/files/issues/node.module_11.patch (951 bytes)

And a patch is ready! Code was based on many example, including this [4]
and this [5] along with adding my own thoughts and what not ;)

[4]
http://www.codestore.org/store.nsf/cmnts/451FA051398A9AF486256EE0000FB7D1?OpenDocument
[5] http://www.blogger.com/app/scripts/formcheck.js

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Mon, 12 Sep 2005 21:10:45 +0000 : m3avrck

Attachment: http://drupal.org/files/issues/formcheck.js (1.54 KB)

And here is the JS to throw in misc/.

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Mon, 12 Sep 2005 21:22:56 +0000 : m3avrck

Attachment: http://drupal.org/files/issues/formcheck_0.js (1.61 KB)

Better JS file attached without tabs. Also, tested and working great in
FF and IE6. Doesn't work in Opera 8, however no errors are present, I
believe this is just because the event handler is not supported. If
there is a work around for Opera, please let me know!

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Mon, 12 Sep 2005 21:24:18 +0000 : m3avrck

Attachment: http://drupal.org/files/issues/formcheck_1.js (1.61 KB)

One more try with those tabs.

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Mon, 12 Sep 2005 21:32:48 +0000 : moshe weitzman

hmmm. i usually find these prompts annoying. any chance we can attach
the behavior only to the node and comment forms? those are the "high
risk" areas. what do others think?

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Mon, 12 Sep 2005 21:42:39 +0000 : m3avrck

Yes, the JS is only loaded on the node edit/create pages, won't affect
any admin/login/etc form. Also, the prompt is unobstrusive and if you
goto save a node you don't get a warning that the contents have changed
because you are explicity saving the node (hence no reason!).