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Use the browser’s Page Visibility API to detect when a React page is hidden, and use window focus and blur only when you need to know whether its window is active. They are different signals: a blurred page may still be visible. Subscribe to the relevant browser events in an effect, clean them up when the component unmounts, and pause only work that does not need to continue.
Visibility and focus tell you different things
The Page Visibility API answers whether a document is visible to the user. Listen for visibilitychange on document, then read document.visibilityState or document.hidden to get the current state. The event itself does not carry the new state. A document can become hidden when someone switches tabs, minimizes the browser, navigates away, closes the page, or switches apps on a mobile device. MDN Web Docs: Page Visibility API and visibilitychange event.
Window focus and blur events answer whether the page’s window is active. They do not reliably tell you whether the document is hidden. As MDN puts it, “watching for blur and focus events on the window helps you know when your page is not the active page, but it does not tell you that your page is actually hidden to the user.” MDN Web Docs: Document.visibilityState.
| Signal | Listen on | Read | Use it when |
|---|---|---|---|
| Page visibility | document |
document.visibilityState or document.hidden |
You need to know whether the document is visible, such as for offscreen polling or animation. |
| Window activity | window |
Track focus and blur in your own state | Behavior specifically depends on whether the window is active, even if the page remains visible. |
The visibilityState property has been available across browsers since July 2015, according to MDN’s reference page, last modified May 8, 2024. Check current compatibility data if your application requires support for a specific browser version.
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Track both signals in a React hook
React does not provide these browser events; use an effect to subscribe to them. This hook initializes with safe defaults for server rendering, reads the actual browser state after mounting, and removes every listener during cleanup:
import { useEffect, useState } from 'react';
export function usePageActivity() {
const [visibilityState, setVisibilityState] = useState('visible');
const [hasWindowFocus, setHasWindowFocus] = useState(false);
useEffect(() => {
if (typeof document === 'undefined' || typeof window === 'undefined') {
return;
}
const updateVisibility = () => {
setVisibilityState(document.visibilityState);
};
const handleFocus = () => setHasWindowFocus(true);
const handleBlur = () => setHasWindowFocus(false);
updateVisibility();
setHasWindowFocus(document.hasFocus());
document.addEventListener('visibilitychange', updateVisibility);
window.addEventListener('focus', handleFocus);
window.addEventListener('blur', handleBlur);
return () => {
document.removeEventListener('visibilitychange', updateVisibility);
window.removeEventListener('focus', handleFocus);
window.removeEventListener('blur', handleBlur);
};
}, []);
return {
visibilityState,
isVisible: visibilityState === 'visible',
hasWindowFocus,
};
}The initial 'visible' value is a safe rendering default, not a claim about the browser before the effect runs. The effect synchronizes the state from the current document and window properties once those browser globals exist. A similar SSR-safe default and listener cleanup are shown in the ReactUse useDocumentVisibility documentation; that is a third-party library example, not a React recommendation.
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Pause work according to the signal it needs
For example, a dashboard can stop polling while hidden and request fresh data when it becomes visible. An animation can pause when hidden, while a product that needs active-window behavior can separately respond to focus changes.
const { isVisible } = usePageActivity();
useEffect(() => {
if (!isVisible) return;
const refresh = () => fetchDashboardData();
refresh();
const intervalId = window.setInterval(refresh, 30_000);
return () => window.clearInterval(intervalId);
}, [isVisible]);Choose the visibility condition for work that is useless when the page is offscreen. Add a focus condition only if active-window status matters to that work or interaction. For instance, an animation might use both isVisible and hasWindowFocus, while polling may need only visibility. Decide whether becoming visible should simply resume a timer or trigger an immediate refresh; the right choice depends on how stale the data can become.
Rank #3
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Do not confuse hidden pages with ended sessions
A hidden document may become visible again, so visibilityState === 'hidden' is not proof that the user has left for good. MDN notes that the transition to hidden is often the last reliably observable lifecycle event in some scenarios and can be useful for ending-session analytics. For sending analytics as a page exits, MDN’s example uses navigator.sendBeacon; do not rely on an unload handler as a substitute. MDN Web Docs: visibilitychange event.
Why explicit pausing still matters
Browsers may throttle timers or stop requestAnimationFrame callbacks for background pages, but this is browser behavior, not an application-level policy. Explicitly stopping unnecessary polling, subscriptions, or other work makes the app’s behavior intentional and lets it refresh or resume according to product needs. No quantified performance improvement is established for this pattern; its value depends on what work your application would otherwise continue doing. MDN Web Docs: Page Visibility API.
Quick Recap
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