Page Visibility API Is the Right Way to Pause Background Tab Polling

Web dashboards that poll servers on a fixed interval continue making requests even when users switch tabs, wasting server resources and draining device battery. The common fix of pausing on window blur and resuming on focus is flawed, as blur fires even when a tab remains fully visible on a second monitor or when a browser extension popup is opened. The correct solution is the Page Visibility API, which uses document.visibilityState and the visibilitychange event to accurately detect whether a tab's content is truly hidden from the user. Replacing blur/focus listeners with visibilitychange stops polling only when the browser is certain the content is not visible, such as during tab switches, minimization, or screen lock. Developers are also cautioned against counting timer ticks to measure time away, since browsers deliberately throttle background timers, making tick-based elapsed-time calculations unreliable.