/* Codeboosh */

Which KeyboardEvent Property Should You Use? Code, Location, Key, keyCode or Which?

There are many different properties on KeyboardEvent including code, location, key, keyCode, metaKey and which among others, but which one should you use?

The answer is really that it depends. Lets have a look at the options.

KeyboardEvent.code

code holds a string that identifies the physical key being pressed. The value is not affected by the current keyboard layout or modifier state, so a particular key will always return the same value.

Source: https://www.w3.org/TR/uievents/#dom-keyboardevent-code

Example

If you press the enter key on the main part of your keyboard, e.code will return Enter. However, if you press it on your numpad it will return NumpadEnter.

document.addEventListener('keydown', function(e) {
    console.log(e.code); // User presses enter on their main keyboard - Enter
    console.log(e.code); // User presses enter on their numpad - NumpadEnter
});

When to use it

If you need to find out what exact key a user has pressed of their keyboard. However, if you just want to know if for example an Enter key was pressed, I would recommend checking out key below.

Current Browser Support

At the time of writing IE, Android Browser and Samsung Internet do not support code, so you would have to use this in combination with another property such as key if you need to support these browsers.

KeyboardEvent.key

key holds a key attribute value corresponding to the key pressed.

Source: https://www.w3.org/TR/uievents/#dom-keyboardevent-key

Example

So if for example you pressed the enter key anywhere on your keyboard, e.key would return Enter.

document.addEventListener('keydown', function(e) {
    console.log(e.code); // User presses enter on their main keyboard - Enter
    console.log(e.code); // User presses enter on their numpad - Enter
});

When to use it

If you need to find out what key a user has pressed of their keyboard and you don’t need to know where on the keyboard they have pressed it. It’s useful for checking for things like Enter or Shift.

Current Browser Support

KeyboardEvent.location

The location attribute contains an indication of the logical location of the key on the device.

Source: https://www.w3.org/TR/uievents/#dom-keyboardevent-location

Here are the values it can return.

ValueDescriptionExample
0Key only has one versionCapsLock
1StartFragmentLeft-hand version of the keyShiftLeft
2Right-hand version of the keyShiftRight

When to use it

If you need to know what keyboard a user is using, for example if you want to know if they are using a numpad. Personally I have never had use for this, but there might be some situations when you need it.

Current Browser Support

Boolean Properties

KeyboardEvent.ctrlKey

Specifies whether the Control key modifier is active.

Source: https://www.w3.org/TR/uievents/#idl-interface-KeyboardEvent-initializers

KeyboardEvent.metaKey

Specifies whether the Meta key modifier is active.

Source: https://www.w3.org/TR/uievents/#idl-interface-KeyboardEvent-initializers

Deprecated Properties

There are a number of deprecated KeyboardEvent properties that you have probably seen before, however it is recommended that you shouldn’t use these for any new work and update any old code if possible, as they may be removed in future browser versions.

KeyboardEvent.charCode (deprecated)

This is deprecated and should no longer be used. See https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/charCode for more details.

KeyboardEvent.keyCode (deprecated)

This is deprecated and should no longer be used. See https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode for more details.

KeyboardEvent.which (deprecated)

This is deprecated and should no longer be used. See https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/which for more details.

Example of all the KeyboardEvent properties used

Just press some keys on your keyboard and the values for each property will be outputted below.