ipython/ipython — pull request #3510 by minrk (2013-07-02 04:50:51+00:00)
Title: use `window.onbeforeunload=` for nav-away warning

Firefox 22 broke `$(window).on("beforeunload")` somehow, for some reason, resulting in always showing a dialog, regardless of the function's return value.

closes #3509

The only fix I could find was resorting to the basic low-level API.