Bring back the Scroll Down feature in Full Screen YouTube videos.

youtube-fullscreen-scroll.js

// ==UserScript==
// @name         YouTube: Bring back Full Screen Scroll Down
// @namespace    qwerty.xyz
// @version      1.2025-08-28
// @description  Bring back the Scroll Down feature in Full Screen YouTube videos.
// @author       Qwerty <[email protected]>
// @source       https://gist.github.com/ackvf/2b4f71534c8131713b51c5f6056d472b
// @icon         https://www.google.com/s2/favicons?sz=64&domain=youtube.com
// @match        https://www.youtube.com/*
// @match        https://youtube.com/*
// @grant        none
// ==/UserScript==

/*

Report bugs at the @source link above or join conversation on reddit

https://www.reddit.com/r/youtube/comments/1k89pof/comment/nb65fcb/

*/

(function () {

	'use strict';

	function check() {
		const target = 'deprecate-fullerscreen-ui';
		const elements = document.querySelectorAll(`[${target}]`);

		if (elements.length == 2) {
			elements.forEach(el => el.removeAttribute(target));

			console.info("Found elements:", elements);
			observer.disconnect();
			observing = false;
		}
	}

	const observer = new MutationObserver(check);
	observer.observe(document, { childList: true, subtree: true });

	let observing = true;

	setTimeout(() => {
		if (!observing) return;
		// Disengage observer after 20 seconds if no elements found - in case YouTube makes changes to the DOM.
		console.info("ERROR in UserScript [YouTube: Bring back Full Screen Scroll Down]. If you see this message, it means that the elements were not present in the DOM. The script has stopped observing changes. Please report this issue so the script can be updated. Thank you!");
		observer.disconnect();
	}, 20000);

})();