JSFiddle - React, Tailwind, and code Playground

HTML

<SPAN><input type="password" name="txtPassword" id="password" />

JavaScript

function capLock(e){
 kc = e.keyCode?e.keyCode:e.which;
 sk = e.shiftKey?e.shiftKey:((kc == 16)?true:false);
 if(((kc >= 65 && kc <= 90) && !sk)||((kc >= 97 && kc <= 122) && sk))
  console.log('caps lock on')
 else
  console.log('caps lock off');
}

$('#password').on('keypress', function(e){
    capLock(e.which)
})