Make a subscreen for a video when video is off-screen; also, provides night mode
1.Makes a sub-video of a Youtube video when the video is off-screen, so you can read comments while watching video.
-Size and location of a sub-video can be adjusted by user
-Sub-video can be closed by user
2."Go to Top" function is added, so when you read too many comments in Youtube video, you can immediately go back to the top of the webpage.
-"Go to Top" button can be cancelled in pop up window on right-top corner
3. Night mode is added, so you could watch your video in dark environment.