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The Page Visibility API in Javascript

It seems there is a Page Visibility API that will let us trigger actions based on the page tab begging active or not.

How it works:

const onVisibilityChange = () => {
    console.log("The current page is now:" + document.hidden);
    // document.hidden will return true or false
}
document.addEventListener("visibilitychange", onVisibilityChange);

For example, a nice application for it will be to play a background sound only when the user is on our page.

let backgroundSound = new Audio('/assets/background.mp3');
const onVisibilityChange = () => {
  const video = document.getElementById("my-video");
  return document.hidden
    ? backgroundSound.pause()
    : backgroundSound.play();
}
document.addEventListener("visibilitychange", onVisibilityChange);

The is also the document.visibilityState that will return 'hidden', 'visible' or 'prerender' (when the website is still loading).

It's quite an old feature (added somewhere around 2011) but only now I've found about it.

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