504322 - window.onbeforeunload doesn't work in FF 3.5

Status: RESOLVED WORKSFORME

(Firefox :: General, defect)

Description

[heythere119]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5

window.onbeforeunload does not execute when the browser window is closed. I am using the following javascript to set the onbeforenload action:

window.onbeforeunload = function (e) {

  var e = e || window.event;

  // For IE and Firefox
  if (e) {
    e.returnValue = 'Message here';
  }
  // For Safari
  return 'Message here';
};

This code worked in FF 3.0 but no longer works in FF 3.5. The window does not prompt the user for confirmation on closing the window. The function never executes.

Reproducible: Always

Steps to Reproduce:
Closing the browser window after setting window.onbeforeunload.
Actual Results:  
Window closes without prompting user for confirmation on closing browser.

Expected Results:  
User is prompted for confirmation in closing the window.

This feature worked in FF 3.0 but no longer works in 3.5.

Comment 1

[Ria Klaassen (not reading all bugmail)]

Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.1pre) Gecko/20090711 Shiretoko/3.5.1pre

This works fine for me. Maybe an add-on is causing problems? Please try safe-mode to find out: http://support.mozilla.com/en-US/kb/Safe+Mode

Comment 2

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

WFM on Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5

Comment 3

[heythere119]

I just noticed that this only occurs when using tabs. If I close the tab it will not prompt for confirmation, but if I try to 'x' out of Firefox completely, the confirmation is displayed.

Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5

Comment 4

[Biju]

WFM
Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.2.11pre) 
Gecko/20100920 Namoroka/3.6.11pre

Mozilla/5.0 (Windows NT 6.0; rv:2.0b7pre) 
Gecko/20100918 Firefox/4.0b7pre

Please test this by disabling extensions one by one.
Let us know if it still appear after disabling all the addons