自用 Tampermonkey 网页倍速快捷键脚本

DryIce-cc

自用脚本，使用键盘快捷键：Alt+< 减速；Alt+>加速；Alt+/ 重置速度。
适用于b站小红书等等大部分网页视频。
// ==UserScript==
// @name         视频倍速快捷键
// @version      1.0
// @match        *://*/*
// @grant        none
// @run-at       document-idle
// ==/UserScript==

(function () {
  'use strict';
  // 速率档位：只在这个列表里前进/后退
  const RATES = [0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 4, 5, 10];
  const DEFAULT_RATE = 1;

  // ---------- 找当前视频 ----------
  function getVideo() {
    const videos = Array.from(document.querySelectorAll('video'));
    if (!videos.length) return null;
    return (
      videos.find(v => !v.paused && !v.ended && v.readyState > 2) ||
      videos.find(v => !v.paused) ||
      videos[0]
    );
  }

  // ---------- 速率逻辑 ----------
  function nearestIndex(rate) {
    let idx = 0, min = Infinity;
    RATES.forEach((r, i) => {
      const d = Math.abs(r - rate);
      if (d < min) { min = d; idx = i; }
    });
    return idx;
  }

  function stepRate(dir) {
    const v = getVideo();
    if (!v) { showToast('未找到视频'); return; }
    let idx = nearestIndex(v.playbackRate) + dir;
    idx = Math.max(0, Math.min(RATES.length - 1, idx)); // 到两端后不再越界
    v.playbackRate = RATES[idx];
    showToast(RATES[idx] + 'x');
  }

  function resetRate() {
    const v = getVideo();
    if (!v) { showToast('未找到视频'); return; }
    v.playbackRate = DEFAULT_RATE;
    showToast(DEFAULT_RATE + 'x');
  }

  // ---------- 唯一保留的 UI：屏幕中央文字提示 ----------
  let toastEl = null, toastTimer = null;
  function showToast(text) {
    if (!toastEl) {
      toastEl = document.createElement('div');
      toastEl.style.cssText = [
        'position:fixed', 'left:50%', 'top:50%',
        'transform:translate(-50%,-50%)',
        'z-index:2147483647',
        'padding:12px 24px',
        'font-size:28px', 'font-weight:bold',
        'color:#fff', 'background:rgba(0,0,0,.65)',
        'border-radius:16px',
        'pointer-events:none', 'user-select:none',
        'white-space:nowrap',
        'opacity:0', 'transition:opacity .25s'
      ].join(';');
    }
    // 全屏时挂到全屏元素内，保证提示可见
    const host = document.fullscreenElement || document.documentElement;
    if (toastEl.parentNode !== host) host.appendChild(toastEl);

    toastEl.textContent = text;
    toastEl.style.opacity = '1';
    clearTimeout(toastTimer);
    toastTimer = setTimeout(() => { toastEl.style.opacity = '0'; }, 600);
  }

  // ---------- 快捷键：Alt + ,  .  /  0 ----------
  document.addEventListener('keydown', (e) => {
    if (!e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) return;
    switch (e.code) {
      case 'Comma': stepRate(-1); break; // Alt+,  减一档
      case 'Period': stepRate(1); break; // Alt+.  加一档
      case 'Slash': resetRate(); break; // Alt+/ 重置为 1
      default: return;
    }
    e.preventDefault();
    e.stopPropagation();
  }, true);
})();