files/en-us/web/api/window/focus_event/index.md
{{APIRef}}
The focus event fires when an element has received focus.
The opposite of focus is {{domxref("Window/blur_event", "blur")}}.
This event is not cancelable and does not bubble.
Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}}, or set an event handler property.
addEventListener("focus", (event) => { })
onfocus = (event) => { }
A {{domxref("FocusEvent")}}. Inherits from {{domxref("UIEvent")}} and {{domxref("Event")}}.
{{InheritanceDiagram("FocusEvent")}}
This interface also inherits properties from its parent {{domxref("UIEvent")}}, and indirectly from {{domxref("Event")}}.
null for security reasons.This example changes the appearance of a document when it loses focus. It uses {{domxref("EventTarget.addEventListener()", "addEventListener()")}} to monitor focus and {{domxref("Window/blur_event", "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);
{{EmbedLiveSample("Live_example")}}
{{Specifications}}
{{Compat}}
Element targets: {{domxref("Element/focus_event", "focus")}} event