Example of *.vtt file (subtitles)
WEBVTT line have to be there.

WEBVTT

1
00:00:01.000 –> 00:00:02.000
First line

2
00:00:03.000 –> 00:00:04.000
Second line

Add javascript:

// Auto-add VTT subtitles for Breakdance videos (works even in new tab)
(function() {
    'use strict';

    const CONFIG = {
        videoSelectors: [
            'video',
            '.bde-video video',
            '.breakdance-video video',
            '.ee-video video'
        ]
    };

    let processedVideos = new Set();

    function initAutoSubtitles() {
        const videos = findAllVideos();

        // Fallback: ak stránka obsahuje len jedno video priamo
        if (videos.length === 0 && document.querySelector('video')) {
            videos.push(document.querySelector('video'));
        }

        videos.forEach((video, index) => {
            const videoId = video.src || video.currentSrc || video.outerHTML.substring(0, 100);
            if (!processedVideos.has(videoId)) {
                processedVideos.add(videoId);
                addVttSubtitle(video, index + 1);
            }
        });
    }

    function findAllVideos() {
        const videos = [];
        CONFIG.videoSelectors.forEach(selector => {
            document.querySelectorAll(selector).forEach(video => {
                if (!videos.includes(video)) videos.push(video);
            });
        });
        return videos;
    }

    function addVttSubtitle(video, videoNumber, attempt = 0) {
        const src = video.src || video.currentSrc;
        if (!src) {
            // Retry if src isn't ready yet
            if (attempt < 5) {
                setTimeout(() => addVttSubtitle(video, videoNumber, attempt + 1), 500);
            }
            return;
        }

        // Extract folder path and file name
        const urlParts = src.split('/');
        const fileName = urlParts.pop().split('.')[0]; // remove extension
        const folderPath = urlParts.join('/') + '/';

        const subtitleUrl = folderPath + fileName + '.vtt';

        // Check if track already exists
        if (video.querySelector('track[kind="subtitles"]')) return;

        const track = document.createElement('track');
        track.kind = 'subtitles';
        track.src = subtitleUrl;
        track.srclang = 'en';
        track.label = 'English';
        track.default = true;

        video.appendChild(track);
        video.load();

        video.addEventListener('loadedmetadata', () => {
            if (video.textTracks && video.textTracks.length > 0) {
                video.textTracks[0].mode = 'showing';
                console.log(`✅ Video ${videoNumber}: Subtitles enabled`);
            }
        });
    }

    // Observe dynamically added videos
    const observer = new MutationObserver(mutations => {
        let newVideo = false;
        mutations.forEach(m => {
            m.addedNodes.forEach(node => {
                if (node.nodeType === 1 && (node.tagName === 'VIDEO' || node.querySelector('video'))) {
                    newVideo = true;
                }
            });
        });
        if (newVideo) setTimeout(initAutoSubtitles, 500);
    });
    observer.observe(document.body, { childList: true, subtree: true });

    // Run on page load
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', initAutoSubtitles);
    } else {
        initAutoSubtitles();
    }

    // Fallback: ensure subtitles load even after full window load
    window.addEventListener('load', () => setTimeout(initAutoSubtitles, 1000));

    console.log('🚀 Breakdance auto-VTT subtitles loaded (works in new tab too)');
})();