A simple script which saves your playback time on YouTube videos for automatically resuming where you left off.
The auto-resume feature is disabled for all channels by default.
You will find the button that enables it located under YouTube player, just above where the channel's name is.
Once enabled, auto-resume feature will start saving playback positions of videos on that particular YouTube channel as you watch them.
If you disable auto-resume on a channel, this will remove previously saved playback positions of all videos on that channel.
The script, by design, does not work on live streams.
Jumping to last saved playback position occurs 3 seconds after a video starts playing.
( unless you have a time-stamp in the video URL. e.g. t=36m15s )
If a video has only 5 per cent of playback time left, the saved playback position will be reset to 0 and the video will be considered fully watched.