EDIT: Figured it out on my own
For whom it may concern, a solution for caps detection in vanilla JavaScript. The problem with most of the solutions floating around on the internet is they only show/hide an alert/popup when the user starts typing in the input field. This is not optimal because the "Caps Lock is on" notification is still visible after the user has turned Caps Lock off, and remains so until they resume typing. This is long and unwieldy, and I still don't quite understand it myself. But I recommend it all the same.
function capsDetect() {
var body = document.getElementsByTagName('body')[0];
var isShiftPressed = false;
var isCapsOn = null;
var capsWarning = document.getElementById('caps-lock-warning');
body.addEventListener('keydown', function(e) {
var keyCode = e.keyCode ? e.keyCode : e.which;
if (keyCode = 16){
isShiftPressed = true;
}
});
body.addEventListener('keyup', function(e) {
var keyCode = e.keyCode ? e.keyCode : e.which;
if(keyCode == 16) {
isShiftPressed = false;
}
if(keyCode == 20) {
if(isCapsOn == true) {
isCapsOn = false;
capsWarning.style.visibility = 'hidden';
} else if (isCapsOn == false) {
isCapsOn = true;
capsWarning.style.visibility = 'visible';
}
}
});
body.addEventListener('keypress', function(e) {
var keyCode = e.keyCode ? e.keyCode : e.which;
if(keyCode >= 65 && keyCode <= 90 && !isShiftPressed) {
isCapsOn = true;
capsWarning.style.visibility = 'visible';
} else {
capsWarning.style.visibility = 'hidden';
}
});
}
shiftCaps();
via Chebli Mohamed
