Youtube Fullscreen Mode

-

Versión del día 18/9/2025. Echa un vistazo a la versión más reciente.

Tendrás que instalar una extensión para tu navegador como Tampermonkey, Greasemonkey o Violentmonkey si quieres utilizar este script.

Necesitarás instalar una extensión como Tampermonkey o Violentmonkey para instalar este script.

Necesitarás instalar una extensión como Tampermonkey o Violentmonkey para instalar este script.

Necesitarás instalar una extensión como Tampermonkey o Userscripts para instalar este script.

Necesitará instalar una extensión como Tampermonkey para instalar este script.

Necesitarás instalar una extensión para administrar scripts de usuario si quieres instalar este script.

(Ya tengo un administrador de scripts de usuario, déjame instalarlo)

Necesitará instalar una extensión como Stylus para instalar este estilo.

Necesitará instalar una extensión como Stylus para instalar este estilo.

Necesitará instalar una extensión como Stylus para instalar este estilo.

Necesitará instalar una extensión del gestor de estilos de usuario para instalar este estilo.

Necesitará instalar una extensión del gestor de estilos de usuario para instalar este estilo.

Necesitará instalar una extensión del gestor de estilos de usuario para instalar este estilo.

(Ya tengo un administrador de estilos de usuario, déjame instalarlo)

// ==UserScript==
// @name              Youtube Fullscreen Mode
// @name:ko           유튜브 풀스크린
// @description       -
// @description:ko    -
// @version           2025.09.18
// @author            ndaesik
// @icon              https://upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Youtube_shorts_icon.svg/193px-Youtube_shorts_icon.svg.png
// @match             *://*.youtube.com/*
// @grant             none
// @namespace https://ndaesik.tistory.com/
// ==/UserScript==

(() => {
  'use strict';
  if (window.top !== window.self) return;

  const suggestBoxToDarkCSS = document.createElement('style');
  suggestBoxToDarkCSS.dataset.tm = 'yt-fullscreen-suggest';
  suggestBoxToDarkCSS.textContent = `
    body{overflow-y:auto;}
  `.replaceAll(';','!important;');

  const fullscreenVideoCSS = document.createElement('style');
  fullscreenVideoCSS.dataset.tm = 'yt-fullscreen-video';
  fullscreenVideoCSS.textContent = `
    ytd-app:not([guide-persistent-and-visible]) [theater] #player video,
    :is(ytd-watch-flexy[theater],ytd-watch-flexy[fullscreen]) #full-bleed-container {
      height:100vh;max-height:100vh;min-height:100vh;
    }
    ytd-watch-flexy[theater]{scrollbar-width:none;}
    ytd-watch-flexy[theater]::-webkit-scrollbar{display:none;}
    ytd-watch-flexy[theater] ~ body{scrollbar-width:none;-ms-overflow-style:none;}
    ytd-watch-flexy[theater] ~ body::-webkit-scrollbar{display:none;}
  `.replaceAll(';','!important;');

  const autoHideTopCSS = document.createElement('style');
  autoHideTopCSS.dataset.tm = 'yt-fullscreen-autohide';
  autoHideTopCSS.className = 'autoHideTopCSS';
  autoHideTopCSS.textContent = `
    #masthead-container.ytd-app:hover,#masthead-container.ytd-app:focus-within{width:100%;}
    #masthead-container.ytd-app,
    #masthead-container.ytd-app:not(:hover):not(:focus-within){width:calc(50% - 150px);}
    #masthead-container.ytd-app:not(:hover):not(:focus-within){transition:width .4s ease-out .4s;}
    ytd-app:not([guide-persistent-and-visible]) :is(#masthead-container ytd-masthead, #masthead-container.ytd-app::after){
      transform:translateY(-56px);transition:transform .1s .3s ease-out;
    }
    ytd-app:not([guide-persistent-and-visible]) :is(#masthead-container:hover ytd-masthead, #masthead-container:hover.ytd-app::after, #masthead-container:focus-within ytd-masthead){
      transform:translateY(0);
    }
    ytd-app:not([guide-persistent-and-visible]) ytd-page-manager{margin-top:0;}
  `.replaceAll(';','!important;');

  const $ = {
    els: { ytdApp: null, player: null, chatFrame: null },
    update() {
      this.els.ytdApp = document.querySelector('ytd-app');
      this.els.player = document.querySelector('#ytd-player');
      this.els.chatFrame = document.querySelector('ytd-live-chat-frame');
    }
  };

  let scrollTimer = null, isContentHidden = false;
  let observerForTheater = null;
  let listenersAttached = false;
  let listenerAbort = null;

  const isWatchPage = () => location.pathname === '/watch';
  const inTheater = () => {
    $.update();
    const { ytdApp, player, chatFrame } = $.els;
    return ytdApp && player && isWatchPage() &&
      (window.innerWidth - ytdApp.offsetWidth + player.offsetWidth +
       (chatFrame && !chatFrame.attributes.collapsed ? chatFrame.offsetWidth : 0)) === window.innerWidth;
  };

  const rafUntil = (pred, timeout = 5000) => new Promise(resolve => {
    const t0 = performance.now();
    const tick = () => {
      if (pred()) return resolve(true);
      if (performance.now() - t0 > timeout) return resolve(false);
      requestAnimationFrame(tick);
    };
    tick();
  });

  const isProgressHidden = () => {
    const p = document.querySelector('yt-page-navigation-progress');
    if (!p) return true;
    if (p.hasAttribute('hidden')) return true;
    const s = getComputedStyle(p);
    return s.display === 'none' || s.visibility === 'hidden' || s.opacity === '0';
  };

  const isPlayerReady = () => {
    const v = document.querySelector('#ytd-player video, #movie_player video, ytd-player video');
    return !!(v && v.readyState >= 1);
  };

  const resetScrollTopSmart = async () => {
    try { if ('scrollRestoration' in history) history.scrollRestoration = 'manual'; } catch(_) {}
    window.scrollTo(0,0);
    await new Promise(r => requestAnimationFrame(() => { window.scrollTo(0,0); r(); }));
    await new Promise(r => requestAnimationFrame(() => { window.scrollTo(0,0); r(); }));
    await rafUntil(() => (document.readyState === 'complete' || isProgressHidden()) && isPlayerReady());
    window.scrollTo(0,0);
  };

  let autoHideOn = false;

  const shouldShowAutoHideCSS = () => {
    const scrollPosition = window.scrollY;
    const viewportHeight = window.innerHeight + 56;
    return isWatchPage() && inTheater() && scrollPosition <= viewportHeight;
  };

  const updateAutoHideCSS = () => {
    const need = shouldShowAutoHideCSS();
    if (need === autoHideOn) return;
    autoHideOn = need;
    if (need) {
      if (!document.head.querySelector('style[data-tm="yt-fullscreen-autohide"]')) {
        document.head.appendChild(autoHideTopCSS);
      }
    } else {
      autoHideTopCSS.remove();
    }
  };

  const checkConditions = () => {
    if (!isWatchPage()) return;
    const watchFlexy = document.querySelector('ytd-watch-flexy');
    const primaryContent = document.querySelector('#primary');
    const secondaryContent = document.querySelector('#secondary');
    const isTheater = watchFlexy?.hasAttribute('theater');
    const isScrollTop = window.scrollY === 0;
    if (!primaryContent || !secondaryContent || !isTheater) return;
    if (isScrollTop && !isContentHidden) {
      if (scrollTimer) clearTimeout(scrollTimer);
      scrollTimer = setTimeout(() => {
        primaryContent.style.display = 'none';
        secondaryContent.style.display = 'none';
        isContentHidden = true;
      }, 2000);
    } else if (!isScrollTop && scrollTimer) {
      clearTimeout(scrollTimer);
      scrollTimer = null;
      if (isContentHidden) {
        primaryContent.style.display = '';
        secondaryContent.style.display = '';
        isContentHidden = false;
      }
    }
  };

  const showContent = () => {
    const primaryContent = document.querySelector('#primary');
    const secondaryContent = document.querySelector('#secondary');
    if (isContentHidden && primaryContent && secondaryContent) {
      primaryContent.style.display = '';
      secondaryContent.style.display = '';
      isContentHidden = false;
      if (scrollTimer) { clearTimeout(scrollTimer); scrollTimer = null; }
      setTimeout(checkConditions, 1000);
    }
  };

  const attachCSS = () => {
    if (!document.head.querySelector('style[data-tm="yt-fullscreen-suggest"]')) {
      document.head.appendChild(suggestBoxToDarkCSS);
    }
    if (!document.head.querySelector('style[data-tm="yt-fullscreen-video"]')) {
      document.head.appendChild(fullscreenVideoCSS);
    }
    updateAutoHideCSS();
  };

  const detachCSS = () => {
    suggestBoxToDarkCSS.remove();
    fullscreenVideoCSS.remove();
    autoHideTopCSS.remove();
    observerForTheater?.disconnect();
    observerForTheater = null;
    if (listenerAbort) { listenerAbort.abort(); listenerAbort = null; }
    listenersAttached = false;
    if (isContentHidden) {
      const primaryContent = document.querySelector('#primary');
      const secondaryContent = document.querySelector('#secondary');
      if (primaryContent) primaryContent.style.display = '';
      if (secondaryContent) secondaryContent.style.display = '';
      isContentHidden = false;
    }
    if (scrollTimer) { clearTimeout(scrollTimer); scrollTimer = null; }
    autoHideOn = false;
  };

  const setupEventListeners = () => {
    if (listenersAttached) return;
    listenersAttached = true;
    listenerAbort = new AbortController();
    const sig = listenerAbort.signal;

    window.addEventListener('scroll', () => requestAnimationFrame(() => {
      updateAutoHideCSS();
      checkConditions();
    }), { passive: true, signal: sig });

    window.addEventListener('click', () => {
      setTimeout(updateAutoHideCSS, 100);
      requestAnimationFrame(showContent);
    }, { passive: true, signal: sig });

    window.addEventListener('wheel', () => requestAnimationFrame(showContent), { passive: true, signal: sig });

    const watchFlexyInit = () => {
      const watchFlexy = document.querySelector('ytd-watch-flexy');
      if (!watchFlexy) return;
      observerForTheater?.disconnect();
      observerForTheater = new MutationObserver(() => requestAnimationFrame(checkConditions));
      observerForTheater.observe(watchFlexy, { attributes: true, attributeFilter: ['theater'] });
    };
    new MutationObserver(watchFlexyInit).observe(document.documentElement, { childList: true, subtree: true });
    watchFlexyInit();

    window.addEventListener('yt-navigate-finish', () => { resetScrollTopSmart(); }, { passive: true, signal: sig });
  };

  const URL_EVENT = 'tm-url-change';
  const fireUrlEvent = () => window.dispatchEvent(new Event(URL_EVENT));

  const _pushState = history.pushState;
  const _replaceState = history.replaceState;
  history.pushState = function(...args) { const r = _pushState.apply(this, args); fireUrlEvent(); return r; };
  history.replaceState = function(...args) { const r = _replaceState.apply(this, args); fireUrlEvent(); return r; };

  window.addEventListener('popstate', fireUrlEvent);
  window.addEventListener('hashchange', fireUrlEvent);
  window.addEventListener('yt-navigate-finish', fireUrlEvent);
  window.addEventListener('yt-navigate-start', fireUrlEvent);

  let lastPath = location.pathname + location.search;

  const onRoute = () => {
    const now = location.pathname + location.search;
    if (now === lastPath) return;
    lastPath = now;
    if (isWatchPage()) {
      attachCSS();
      setupEventListeners();
      resetScrollTopSmart();
      requestAnimationFrame(() => {
        updateAutoHideCSS();
        checkConditions();
      });
    } else {
      detachCSS();
    }
  };

  const boot = () => {
    if (isWatchPage()) {
      attachCSS();
      setupEventListeners();
      resetScrollTopSmart();
      requestAnimationFrame(() => {
        updateAutoHideCSS();
        checkConditions();
      });
    } else {
      detachCSS();
    }
  };

  window.addEventListener(URL_EVENT, onRoute);
  boot();
})();