Firefox 4 onBeforeUnload custom message

Question

In Firefox 3, I was able to write a custom confirmation popup with:

window.onbeforeunload = function() {
   if (someCondition) {
      return 'Your stream will be turned off';
   }
}

Now in Firefox 4, it does not show my custom message. The default message that it provides is not even accurate to what my application does.

Can this default message be overridden?

Answer 1

From MDN:

Note that in Firefox 4 and later the returned string is not displayed to the user. See Bug 588292.

This "Bug" is actually a (imho questionable) feature.. so there's no way to display the message in Firefox 4. If you think it should be changed, comment on that bug so the Firefox developers will know that people actually want to be able to show a custom string.