This extension does not add any UI element and uses no resource at all. Only on YouTube pages, a very tiny script is injected which controls the player’s playing status based on document visibility status. When a YouTube tab is brought to the front, the player automatically resumes exactly like pressing the play button and when the document is hidden, the player will automatically pause exactly like when the pause button is pressed.
For FAQs and other useful YouTube enhancer extensions please visit:
0.1.1: It is possible to disable and re-enable the extension from the toolbar button. This is useful when you want to listen to YouTube videos in a background tab.