Pick a duration, drag the button to your bookmarks bar, and click it once on any YouTube watch page. The bookmarklet captures the moment you are at and repeats the next few seconds on a tight interval. No install, no account.
This is the exact JavaScript that runs when you click the bookmark on a YouTube page. Read it before you install. It only touches the current tab.
This is a single-purpose bookmarklet, kept tiny on purpose. It is honest about its limits.
If you want loops that remember themselves, custom A and B markers, speed control, and shortcut keys, install the full extension below.
Get YouTube Looper ProIt works on any standard YouTube watch page that uses the regular HTML5 video player. On YouTube Shorts the player markup is different and the bookmarklet may not attach. Embedded players on third-party sites are also out of scope.
A bookmarklet runs once per click and has no storage. After a page reload nothing remembers the loop. Click the bookmark again to re-arm it, or use YouTube Looper Pro which saves loops per video and restores them automatically.
When the loop is active a small banner appears in the bottom right of the page. Click "Click to clear." and the interval stops. You can also click the bookmark again to replace the loop with a new one starting at the current moment.
The bookmarklet only runs inside the current YouTube tab in your browser. It does not send data anywhere, has no external dependencies, and does not require permissions. Read the full source in the code block above before you install it.
Some browsers and corporate device policies block bookmarklet creation by drag and drop. Right-click the red button and pick "Add to bookmarks" or "Bookmark this link". You can also open the bookmark manager, create a new bookmark, and paste the javascript URL into the URL field by hand.