YouTube Focus

Nothing under the video you are watching, and no autoplay into another one. For Safari on iPhone with the free Userscripts extension.

Install YouTube Focus
  1. Tap the red button above. Safari shows the script as text.
  2. Tap the ••• button next to the address bar (usually at the bottom of the screen) and tap Userscripts. Not there? Tap the small icon at the left edge inside the address bar instead. On older iPhones this button is labelled AA.
  3. If Safari asks, choose Always Allow, then Always Allow on Every Website. Then tap Install in the Userscripts popup.
  4. Userscripts missing from both menus? Go to Settings, Apps, Safari, Extensions, Userscripts: turn on Allow Extension and set All Websites to Allow, then come back here.
  5. Open m.youtube.com in Safari and play any video. The space under it should be empty.