The blur event fires when an element has lost focus.

The opposite of blur is focus.

This event is not cancelable and does not bubble.

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("blur", (event) => {});

onblur = (event) => {};

A FocusEvent. Inherits from Event.

This interface also inherits properties from its parent UIEvent, and indirectly from Event.

FocusEvent.relatedTarget

An EventTarget representing a secondary target for this event. In some cases (such as when tabbing in or out a page), this property may be set to null for security reasons.

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

The value of Document.activeElement varies across browsers while this event is being handled (Firefox bug 452307): IE10 sets it to the element that the focus will move to, while Firefox and Chrome often set it to the body of the document.

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