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