Scripts for controlling youtube videos. Now maintained at https://github.com/fent/dotfiles/tree/master/scripts

youtube_next.applescript

# If in a playlist, play the next video.
tell application "Google Chrome"
  repeat with t in tabs of windows
    tell t
      if URL starts with "http://www.youtube.com/watch" or URL starts with "https://www.youtube.com/watch" then
        execute javascript "
        var player =
          document.getElementById('movie_player') ||
          document.getElementsByTagName('embed')[0];
        var next = document.getElementsByClassName('yt-uix-button-icon-playlist-bar-next')[0];
        if (player && next) {
          next.click();
        }
        "
        exit repeat
      end if
    end tell
  end repeat
end tell

youtube_pause_all.applescript

# Pause all youtube videos in all youtube tabs.
tell application "Google Chrome"
  repeat with t in tabs of windows
    tell t
      if URL starts with "http://www.youtube.com/watch" or URL starts with "https://www.youtube.com/watch" then
        execute javascript "
        var player =
          document.getElementById('movie_player') ||
          document.getElementsByTagName('embed')[0];
        if (player) {
          player.pauseVideo();
        }
        "
      end if
    end tell
  end repeat
end tell

youtube_play_pause.applescript

# Play or pause a video.
tell application "Google Chrome"
  repeat with t in tabs of windows
    tell t
      if URL starts with "http://www.youtube.com/watch" or URL starts with "https://www.youtube.com/watch" then
        execute javascript "
        var player =
          document.getElementById('movie_player') ||
          document.getElementsByTagName('embed')[0];
        if (player) {
          if (player.getPlayerState() === 1) {
            player.pauseVideo();
          } else {
            player.playVideo();
          }
        }
        "
        exit repeat
      end if
    end tell
  end repeat
end tell

youtube_previous.applescript

# If in a playlist and the current video time is <= 5 seconds,
# play the previous video,
# otherwise, rewind to the beginning of the current video and play.
tell application "Google Chrome"
  repeat with t in tabs of windows
    tell t
      if URL starts with "http://www.youtube.com/watch" or URL starts with "https://www.youtube.com/watch" then
        execute javascript "
        var player =
          document.getElementById('movie_player') ||
          document.getElementsByTagName('embed')[0];
        if (player) {
          var prev = document.getElementsByClassName('yt-uix-button-icon-playlist-bar-prev')[0];
          if (player.getCurrentTime() <= 5 && prev) {
            prev.click();
          } else {
            player.seekTo(0, true);
            if (player.getPlayerState() !== 1) {
              player.playVideo();
            }
          }
        }
        "
        exit repeat
      end if
    end tell
  end repeat
end tell

These will not work with the latest chrome version anymore. I have created some updated scripts to use with the new chrome version which can be found here https://gist.github.com/zachloubier/9b07fd21292a7dfb92d9.

I used these scripts as inspiration and just replaced the youtube api with vanilla js.

Can you make a script that set a timer to automatically pause on YouTube? On Firefox?