Turn Off the Lights Browser Extension - Version 1.0 Turn Off the Lights is a free extension for your browser. It provides focus to a video you are watching and makes everything around the video go dark. It works for all video sites such as YouTube, Vimeo,... and also on the social networking sites. When the installation is complete, you will see the light gray lamp listed in the toolbar (or Omnibar). And with one click of the button the page is darkened, providing better focus to the video.