Force bind the spacebar to play/pause videos
< Feedback on Youtube: Spacebar to Play/Pause Videos
I tested in incognito mode and found that if I did not use alt-tab first, the video would not be able to be paused or played using the space bar. Only after using alt-tab can the space bar be used to play and pause normally.
A very good script that solves the problem of not being able to use the space bar after alt-tab returns.