When activated on YouTube.com, this bookmarklet will pause the video when you switch to a different tab or window. It resumes the video when you return.
Drag this link to your bookmarks toolbar: yt-pause-on-blur
Assuming the bookmarklet has been installed,
- Go to a video on YouTube.com
- Click yt-pause-on-blur in your bookmarks toolbar. Note the black box that appeared at the bottom left of the window.
- Switch away from and back to the YouTube tab.
Do one of:
- Click the "Off" button in the bottom left corner, or
- Reload the page