How to tell if browser/tab is active

Advanced stages - essential concepts and optimizations

Window focus and blur events for tab status

For situations where direct engagement with your web app is essential, wield the window focus and blur events to accurately toggle between active and inactive states.

let listenerHere = true;

window.onfocus = () => {
  listenerHere = true;
  // Your logic when the listener has arrived
};

window.onblur = () => {
  listenerHere = false;
  // Ease the activity when the listener steps out
};


This method complements the Page Visibility API, especially when continuous monitoring isn't a necessity.

Intelligent use of intervals and timeouts

Use setInterval and window.setTimeout() smartly. Halt the interval when the window loses focus to stop code execution:

let interval;

window.onfocus = () => {
  interval = setInterval(() => console.log('Still here? Wow!'), 1000); // Just checking! :)
};

window.onblur = () => {
  clearInterval(interval); // Okay, I get the hint!
};


By doing so, your application eases up on resources in inactive tabs, improving the browser's efficiency and prolonging the battery power.

Balancing user experience with resource usage

Balancing user experience with efficient resource utilization is key. You should pause or reduce CPU/GPU-intensive tasks like video playback or gaming when a tab is inactive.

Monitoring tab activity across multiple tabs

Track the activity state across all tabs in which your app is open:

$(window).data('prevType', '');

window.onblur = window.onfocus = (event) => {
  if ($(window).data('prevType') !== event.type) { // Prevent double firing
    listenerHere = event.type === "focus";
  }
  $(window).data('prevType', event.type);
};


This mechanism effectively ensures double-firing prevention, and it's particularly beneficial in maintaining jQuery compatibility.

Tricky nuances with window hover

Using $(window).hover() can be misleading while assessing foreground activity, especially when user’s mouse remains stationary:

$(window).hover(
  () => { /* It might be a false hope! */ },
  (event) => { if (event.fromElement) { /* Oops, tab became inactive again! */ } }
);


Best practices for enhancing user experience

Handling resource-intensive tasks

For CPU-intensive tasks, consider tuning them down when the tab isn't active. This ensures a smooth user experience by preventing unnecessary background utilization of resources.

Considering jQuery compatibility

Ensure your implementation gracefully handles jQuery focus/blur for wider browser compatibility:

$(window).on("blur focus", function(e) {
    const prevType = $(this).data("prevType");

    if (prevType !== e.type) {   // Reduced chances of double firing
        e.type === "focus" ? listenerHere = true : listenerHere = false;
        // It's like a game of hide and seek!
    }

    $(this).data("prevType", e.type);
})


Adapting to different browser versions

Plan for progressive enhancements for your website, considering older browser versions. While most modern browsers support the Page Visibility API, setting up fallbacks guarantees a consistent user experience.

Important points for developers to ponder

Ensuring browser compatibility

Ensure your solution works across all major browser platforms such as Firefox, Safari and Chrome. This guarantees uniform functionality.

Optimizing user-specific interactions

Respect your user's attention by prioritizing interaction and pausing unnecessary animations when the tab is inactive. This conserves resources and increases user satisfaction.

Coordinating interaction across multiple tabs

When your app is open in many tabs, it's helpful for the code to be aware of each tab's state, to avoid overlapping actions such as playing an audio in an inactive tab.