Window: focus event

The focus event fires when an element has received focus.

The opposite of focus is blur.

This example changes the appearance of a document when it loses focus. It uses addEventListener() to monitor focus and blur events.

HTML

<p id="log">Click on this document to give it focus.</p>

CSS

.paused {
  background: #ddd;
  color: #555;
}

JavaScript

function pause() {
  document.body.classList.add('paused');
  log.textContent = 'FOCUS LOST!';
}

function play() {
  document.body.classList.remove('paused');
  log.textContent = 'This document has focus. Click outside the document to lose focus.';
}

const log = document.getElementById('log');

window.addEventListener('blur', pause);
window.addEventListener('focus', play);

Result

• Related event: blur
• This event on Element targets: focus event