This Chrome extension (Subtitles for YouTube) already can overlay custom subtitles on youtube. It will even automatically search external subtitle websites for

This Chrome extension (Subtitles for YouTube) already can overlay custom subtitles on youtube. It will even automatically search external subtitle websites for the url of the video you're viewing and load subtitles for that video from those websites. https://chrome.google.com/webstore/detail/subtitles-for-youtube/oanhbddbfkjaphdibnebkklpplclomal https://chrome.google.com/webstore/detail/subtitles-for-yout...