Document: keydown event

The keydown event is fired when a key is pressed.

Unlike the keypress event, the keydown event is fired for all keys, regardless of whether they produce a character value.

Bubbles Yes
Cancelable Yes
Interface KeyboardEvent
Event handler property onkeydown

The keydown and keyup events provide a code indicating which key is pressed, while keypress indicates which character was entered. For example, a lowercase "a" will be reported as 65 by keydown and keyup, but as 97 by keypress. An uppercase "A" is reported as 65 by all events.

Examples

addEventListener keydown example

This example logs the KeyboardEvent.code value whenever you press down a key.

<p>Focus the IFrame first (e.g. by clicking in it), then try pressing some keys.</p>
<p id="log"></p>
document.addEventListener('keydown', logKey);

function logKey(e) {
  log.textContent += ` ${e.code}`;
}

onkeydown equivalent

document.onkeydown = logKey;

Ignoring keydown during IME composition

An Input Method Editor (IME) is a program that enables users to enter characters that are not supported by their keyboard using some other key combination.

Since Firefox 65, the keydown and keyup events are now fired during IME composition (bug 354358). To ignore all keydown events that are part of composition, do something like this (229 is a special value set for a keyCode relating to an event that has been processed by an IME):

eventTarget.addEventListener("keydown", event => {
  if (event.isComposing || event.keyCode === 229) {
    return;
  }
  // do something
});

Specifications

Specification
UI Events
# event-type-keydown

Browser compatibility

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See also