Detect Caps Lock with JavaScript

Anybody is able to having their caps lock key on at any given time with out realizing so. Customers can simply spot undesirable caps lock when typing in most inputs, however when utilizing a password enter, the issue is not so apparent. That results in the person’s password being incorrect, which is an annoyance. Ideally builders may let the person know their caps lock key’s activated.

To detect if a person has their keyboard’s caps lock activate, we’ll make use of KeyboardEvent‘s getModifierState methodology:

doc.querySelector('enter[type=password]').addEventListener('keyup', operate (keyboardEvent) {
    const capsLockOn = keyboardEvent.getModifierState('CapsLock');
    if (capsLockOn) {
        // Warn the person that their caps lock is on?
    }
});

I might by no means seen getModifierState used earlier than, so I explored the W3C documentation to find different helpful values:

dictionary EventModifierInit : UIEventInit {
  boolean ctrlKey = false;
  boolean shiftKey = false;
  boolean altKey = false;
  boolean metaKey = false;

  boolean modifierAltGraph = false;
  boolean modifierCapsLock = false;
  boolean modifierFn = false;
  boolean modifierFnLock = false;
  boolean modifierHyper = false;
  boolean modifierNumLock = false;
  boolean modifierScrollLock = false;
  boolean modifierSuper = false;
  boolean modifierSymbol = false;
  boolean modifierSymbolLock = false;
};

getModifierState supplies a wealth of perception as to the person’s keyboard throughout key-centric occasions. I want I had identified about getModifier earlier in my profession!

See Also

Supercharge compression effectivity with shared dictionaries  |  Weblog  |  Chrome for Builders