The focus event fires when an element has received focus.
The opposite of focus is blur.
This event is not cancelable and does not bubble.
Use the event name in methods like addEventListener(), or set an event handler property.
addEventListener("focus", (event) => { })
onfocus = (event) => { }A FocusEvent. Inherits from UIEvent and Event.
This example changes the appearance of a document when it loses focus. It uses addEventListener() to monitor focus and blur events.
<p id="log">Click on this document to give it focus.</p>.paused {
background: #dddddd;
color: #555555;
}const log = document.getElementById("log");
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.";
}
window.addEventListener("blur", pause);
window.addEventListener("focus", play);