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

[rjollos]

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.

[rjollos]

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.

[rjollos]

(In [12419]) Refs #10656:

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

[rjollos]

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

[jun66j5]

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.

[rjollos]

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?

[rjollos]

(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).

[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.

[rjollos]

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.