beforeunload event does not fire in MobileSafari on iOS. This is inconsistent with the HTML specification and with Safari on macOS. It is therefore confusing for Web developers that this event does not fire.
Created attachment 414464 [details]
Comment on attachment 414464 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=414464&action=review
Might be worth mentioning that iOS already fires the unload event, so running an event at this time is not a significant change in policy.
Created attachment 414466 [details]
Created attachment 414470 [details]
Committed r269983: <https://trac.webkit.org/changeset/269983>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 414470 [details].