I'm using your script together with http://userscripts.org/scripts/show/31864 and when I open a youtube video in one tab and then switch to another tab before the youtube one even loads, it doesn't autoplay. I tried disabling Comfort in Black to see if the error is perhaps in the YouTube HQ + 720p Revised script, but no, it seems it is in your script. Could you look into this? Thanks! Otherwise I like the script, good work.

Not really a big issue though, as it takes less than a second to switch between two tabs to make the youtube video page active and then switch back to a different tab.