Keeping a tab “visible” to the page when it is in the background

A web page can tell, at any moment, whether you are looking at it. That is how videos pause, games freeze and chats mark you as away the instant you switch tabs.

How pages find out

The Page Visibility API gives every page document.hidden and document.visibilityState, plus a visibilitychange event that fires when you switch away or come back. Pages also get blur and focus events on the window, and can ask document.hasFocus() at any time. Chrome additionally records visibility changes in the page’s performance timeline.

None of these need permission. Any site can use them.

Making a tab look always visible

For a tab you protect, TabRevive answers those questions as if the tab were still in front: visible, focused. The events that would only fire because you left or came back are not delivered, so the page has nothing to react to. In-page focus changes, like moving between text fields, still work normally.

Chrome still stops drawing a page you can’t see, so CSS animations pause and checks for what is on screen report nothing. Leaving full screen by switching tabs is also visible to the page. These are browser limits no extension can change.