Hi, This morning I finally updated my MacBook Pro from safari 7.0 to safari 9.2. I was not aware of the effect it would have on youtube, as for it completely messed up my fullscreen view and added lag, among many other issues. I have searched all morning for a way to fix this issue, but was unsuccessful. Can someone tell me how I can either turn off HTML5 player for youtube on Safari or how I can safely (without untrusted websites that hold potential viruses or without downloading something that will completely corrupt my whole laptop) downgrade back to Safari 7.0? Thank you so much for any help you can provide, this is really stressing me out!!