key vs keyCode vs which
Written byPhuoc Nguyen
Created
16 Jun, 2020
Category
DOM
`key`, `keyCode` and `which` can be used to determine which key is pressed. Following is a sample code that handles the `keyPress` event of a text box.It checks if user presses the Enter key whose key code is 13:
js
textBoxElement.addEventListener('keydown', function (e) {
if (e.keyCode === 13) {
// Do something ...
}
});#Difference
According to MDN documentations, both keyCode and which are deprecated and will be removed from the Web standards.
Apart from that, both properties are supported differently by browsers. Some browsers use
`keyCode`, other use `which`.It's common to see how they are normalized as following:
js
const key = 'which' in e ? e.which : e.keyCode;
// Or
const key = e.which || e.keyCode || 0;#Good practice
It's recommended to use the key property.
The sample code above can be rewritten as
js
if (e.key === 'Enter') {
// Enter is pressed
}
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Phước Nguyễn