Closed
Description
"""
The exact handling of the unload event has varied from version to version of browsers. For example, some versions of Firefox trigger the event when a link is followed, but not when the window is closed. In practical usage, behavior should be tested on all supported browsers, and contrasted with the PROPRIETARY beforeunload event.
"""
"Proprietary"?? What does that mean? That sounds like it means "non-standard, implemented by some browsers". But it has been standardided in html5. Or am I missing something?