const capsElement = document.querySelector("#caps-led");

​

​

document.addEventListener("keypress",

                          (e)=> {

  let result = isCapslock(e);

  console.log(`caps ${result}`);

  capsElement.classList.toggle("on", result);

});

​

function isCapslock(e){

    e = (e) ? e : window.event;

​

    let charCode = e.keyCode;

    let shifton = false;

   if (e.shiftKey) {

        shifton = e.shiftKey;

    } else if (e.modifiers) {

        shifton = !!(e.modifiers & 4);

    }

​

    if (charCode >= 97 && charCode <= 122 && shifton) {

        return true;

    }

​

    if (charCode >= 65 && charCode <= 90 && !shifton) {

        return true;

    }

​

    return false;

​

}