// ==UserScript== // @name YouTube Caption Downloader // @namespace web.nextbyte.ai // @version 1.0 // @description Download YouTube captions in English or selected language with a button next to the like button // @author NextByte // @match *://www.youtube.com/watch* // @grant none // ==/UserScript== (function() { 'use strict'; // Function to extract caption data from YouTube's player response function getCaptionData() { try { // Try to get caption data from ytInitialPlayerResponse if (window.ytInitialPlayerResponse && window.ytInitialPlayerResponse.captions) { const captionData = window.ytInitialPlayerResponse.captions.playerCaptionsTracklistRenderer; if (captionData && captionData.captionTracks) { return captionData.captionTracks; } } return null; } catch (e) { console.error('Error extracting caption data:', e); return null; } } // Function to download captions async function downloadCaptions(captionUrl, languageName) { try { // Fetch the caption data const response = await fetch(captionUrl); const captionText = await response.text(); // Parse XML and convert to plain text const parser = new DOMParser(); const xmlDoc = parser.parseFromString(captionText, 'text/xml'); const textElements = xmlDoc.getElementsByTagName('text'); let plainText = ''; for (let i = 0; i < textElements.length; i++) { const text = textElements[i].textContent; // Decode HTML entities const decodedText = text.replace(/&/g, '&') .replace(/</g, '<') .replace(/>/g, '>') .replace(/"/g, '"') .replace(/'/g, "'"); plainText += decodedText + '\n'; } // Get video title for filename const videoTitle = document.querySelector('h1.ytd-watch-metadata yt-formatted-string')?.textContent || 'captions'; const sanitizedTitle = videoTitle.replace(/[^a-z0-9]/gi, '_').toLowerCase(); // Create and download file const blob = new Blob([plainText], { type: 'text/plain' }); const url = URL.createObjectURL(blob); const a = document.createElement('a'); a.href = url; a.download = `${sanitizedTitle}_${languageName}.txt`; document.body.appendChild(a); a.click(); document.body.removeChild(a); URL.revokeObjectURL(url); console.log('Captions downloaded successfully!'); } catch (e) { console.error('Error downloading captions:', e); alert('Failed to download captions. Please try again.'); } } // Function to create the download button function createDownloadButton() { // Check if button already exists if (document.getElementById('caption-download-btn')) { return; } // Find the button container (next to like button) - specifically in watch page const buttonContainer = document.querySelector('ytd-watch-metadata #top-level-buttons-computed'); if (!buttonContainer) { console.log('Button container not found, will retry...'); return; } // Get caption data const captionTracks = getCaptionData(); if (!captionTracks || captionTracks.length === 0) { console.log('No captions available for this video'); return; } // Create button wrapper const buttonWrapper = document.createElement('yt-button-view-model'); buttonWrapper.className = 'ytd-menu-renderer'; buttonWrapper.id = 'caption-download-btn'; // Create button const button = document.createElement('button'); button.className = 'yt-spec-button-shape-next yt-spec-button-shape-next--tonal yt-spec-button-shape-next--mono yt-spec-button-shape-next--size-m yt-spec-button-shape-next--icon-leading'; button.style.marginLeft = '8px'; button.setAttribute('aria-label', 'Download captions'); // Button content button.innerHTML = `

Captions

`; // Add click handler button.addEventListener('click', async (e) => { e.preventDefault(); e.stopPropagation(); // If there's only one caption track, download it directly if (captionTracks.length === 1) { const track = captionTracks[0]; const languageName = track.name?.simpleText || track.languageCode || 'unknown'; await downloadCaptions(track.baseUrl, languageName); } else { // Show language selection menu showLanguageMenu(captionTracks, button); } }); buttonWrapper.appendChild(button); buttonContainer.appendChild(buttonWrapper); console.log('Caption download button added successfully!'); } // Function to show language selection menu function showLanguageMenu(captionTracks, buttonElement) { // Remove existing menu if any const existingMenu = document.getElementById('caption-lang-menu'); if (existingMenu) { existingMenu.remove(); } // Create menu const menu = document.createElement('div'); menu.id = 'caption-lang-menu'; menu.style.cssText = ` position: absolute; background: var(--yt-spec-menu-background); border-radius: 12px; box-shadow: 0 4px 32px rgba(0,0,0,0.1); padding: 8px 0; z-index: 10000; min-width: 200px; max-height: 400px; overflow-y: auto; `; // Position menu below button const rect = buttonElement.getBoundingClientRect(); menu.style.top = (rect.bottom + window.scrollY + 8) + 'px'; menu.style.left = rect.left + 'px'; // Add menu items captionTracks.forEach(track => { const languageName = track.name?.simpleText || track.languageCode || 'Unknown'; const item = document.createElement('div'); item.style.cssText = ` padding: 10px 16px; cursor: pointer; color: var(--yt-spec-text-primary); font-size: 14px; `; item.textContent = languageName; item.addEventListener('mouseenter', () => { item.style.backgroundColor = 'var(--yt-spec-10-percent-layer)'; }); item.addEventListener('mouseleave', () => { item.style.backgroundColor = 'transparent'; }); item.addEventListener('click', async () => { menu.remove(); await downloadCaptions(track.baseUrl, languageName); }); menu.appendChild(item); }); // Close menu when clicking outside const closeMenu = (e) => { if (!menu.contains(e.target) && e.target !== buttonElement) { menu.remove(); document.removeEventListener('click', closeMenu); } }; setTimeout(() => { document.addEventListener('click', closeMenu); }, 100); document.body.appendChild(menu); } // Function to initialize the script function init() { // Wait for the page to load const observer = new MutationObserver((mutations, obs) => { const buttonContainer = document.querySelector('ytd-watch-metadata #top-level-buttons-computed'); if (buttonContainer) { createDownloadButton(); // Keep observing for navigation changes } }); observer.observe(document.body, { childList: true, subtree: true }); // Also try to create button immediately if elements exist setTimeout(createDownloadButton, 1000); } // Handle YouTube's SPA navigation let lastUrl = location.href; new MutationObserver(() => { const url = location.href; if (url !== lastUrl) { lastUrl = url; // Remove old button on navigation const oldButton = document.getElementById('caption-download-btn'); if (oldButton) { oldButton.remove(); } // Wait a bit for new page to load, then add button setTimeout(createDownloadButton, 2000); } }).observe(document, { subtree: true, childList: true }); // Start the script init(); console.log('YouTube Caption Downloader loaded!'); })();