The Document.hidden read-only property returns a Boolean value indicating if the page is considered hidden or not. 
 
 
document.addEventListener("visibilitychange", () => {
  console.log(document.hidden);
  
});
   Warning: Due to prerendering, it may happen that document.hidden is true, even if the page is actually visible to the user. In such scenario the page load starts with document.visibilityState = "prerender" and transitions to document.visibilityState = "visible" after some delay. This scenario can be reproduced by opening a new browser tab in Safari, pasting a URL in the URL bar, and navigating to that URL.