Google’s countdown timer effectively updates the time in the browser tab’s title, even when users navigate to other tabs. This seamless functionality relies on efficient background execution to keep the countdown active. I’m working on implementing a similar feature but facing an issue: the title stops updating or lags when the user leaves the tab.
To address this, I tried several approaches, including Web Workers, WebSockets, and requestAnimationFrame. Unfortunately, none fully resolved the issue because browsers tend to throttle background processes in inactive tabs to optimize resource usage, especially for battery life on mobile devices.
Here’s an example of what I attempted using requestAnimationFrame:
let countdown = 60; // Countdown duration in seconds
function updateTitle() {
if (countdown > 0) {
document.title = `Time Left: ${countdown}s`;
countdown--;
requestAnimationFrame(updateTitle);
} else {
document.title = "Time's up!";
}
}
updateTitle();
While this works well in an active tab, the browser throttles requestAnimationFrame when the tab is inactive, causing the timer to freeze or lag. Using setInterval faces a similar challenge, as it’s also throttled in inactive tabs.
To tackle this, I explored Web Workers, which can run JavaScript in the background without being affected by the browser’s main thread. Here’s a simplified example:
Worker Script (timerWorker.js):
let countdown = 60;
setInterval(() => {
if (countdown > 0) {
postMessage(countdown--);
}
}, 1000);
Main Script:
const worker = new Worker('timerWorker.js');
worker.onmessage = function (e) {
document.title = `Time Left: ${e.data}s`;
};
worker.postMessage('start');
While Web Workers help decouple processes, they do not update the DOM directly and can still encounter throttling in some scenarios. The Web Worker approach works for a longer period before it’s stops updating. Thanks for your help in advance.
