It's funny that unpaid developers who release ROMs for my Android phone apparently do a better job at QA than the people at Apple.
https://bugs.webkit.org/attachment.cgi?id=268394&action=diff
Which is why I'm hear to tell Apple: fix your freakibg regressions in Safari quickly. There is absolutely no reason why the browsers rendering engine can only be updated every three months!
Sort it out Apple. You force all web apps to use your engine and prevent effective completion in this space: fine. But you now face the burden on ensuring you prevent and fix your bugs quickly!
Example: a few months ago Safari had a bug where it was still using apple's old WWDR certificate, preventing anyone from packaging their safari extensions. The fix came out months later in the next OS release.
That clear enough for you now?
Sorry :-(