Prompt with a warning dialog when navigating away from a page with unsaved changes to an enum list

[Ryan J Ollos]

When items in the list have been reordered, but the changes haven't yet be saved, a warning should be issued when navigating away from the page. As an example, the BacklogPlugin has this behavior.

[Ryan J Ollos]

I'd like to prompt with the dialog when Remove selected items is pressed, but not when Apply changes is pressed. I'm currently following the guidance in the first reply ​here.

[Ryan J Ollos]

(In [12419]) Refs #10656:

• Prompt user with a dialog when navigating away from a page with unsaved changes to a list.
• Added a changelog.

[Ryan J Ollos]

[12419] doesn't seem to be working correctly with Trac 0.11.

[Jun Omae]

Replying to rjollos:

[12419] doesn't seem to be working correctly with Trac 0.11.

Yes, beforeunload event doesn't work on jQuery 1.2. It works on 1.4. See ​http://bugs.jquery.com/ticket/4106.

Proposal patch is here, t10656-beforeunload-jquery1.2-r12424.diff​. It checks existence of jQuery.event.special.beforeunload. See ​http://benalman.com/news/2010/03/jquery-special-events/#version-compatibility and ​http://docs.jquery.com/Events/jQuery.Event#Special_Events.

[Ryan J Ollos]

Replying to jun66j5:

Proposal patch is here, t10656-beforeunload-jquery1.2-r12424.diff​.

Thanks! Supporting these older versions of jQuery is a pain.

I was trying, but could not understand the need for:

$(window).bind('unload', function() { window.onbeforeunload = null; });

Any hints as to why that is needed?

[Ryan J Ollos]

(In [12436]) Refs #10656: beforeunload event is not supported in jQuery < 1.4, so some special handling is needed to directly utilize the window.onbeforeunload event in the cases that the jQuery special event is not supported. Patch by Jun Omae (jun66j5).

[Jun Omae]

Replying to rjollos:

I was trying, but could not understand the need for: $(window).bind('unload', function() { window.onbeforeunload = null; });

This code is avoiding memory leak risk on Internet Explorer.

[Ryan J Ollos]

Replying to jun66j5:

This code is avoiding memory leak risk on Internet Explorer.

In [12458] I added a note to the source code about this.

[Ryan J Ollos]

Replying to jun66j5:

Replying to rjollos:

I was trying, but could not understand the need for: $(window).bind('unload', function() { window.onbeforeunload = null; });

This code is avoiding memory leak risk on Internet Explorer.

I'm preparing the code for integration into Trac and trying to determine if this is still needed. Does it apply to all versions of Internet Explorer?

[Ryan J Ollos]

Replying to rjollos:

Replying to jun66j5:

Replying to rjollos:

I was trying, but could not understand the need for: $(window).bind('unload', function() { window.onbeforeunload = null; });

This code is avoiding memory leak risk on Internet Explorer.

I'm preparing the code for integration into Trac and trying to determine if this is still needed. Does it apply to all versions of Internet Explorer?

On closer look it appears that is only for the case of support jQuery < 1.4.