JSFiddle - React, Tailwind, and code Playground

HTML

<div id="output"></div>

CSS

div#output {
    background-color: #AAA;
    width: 200px;
    height: 50px;
    text-align: center;
    font-size: 40px;
}
div#output.ctrlKey {
    background-color: #0F0;
}
div#output.noCtrlKey {
    background-color: #F00;
}

JavaScript

var o = document.getElementById('output');

function applyState (state) {
    this.innerHTML = state;
    if (state)
        this.className = 'ctrlKey';
    else
        this.className = 'noCtrlKey';    
}

o.addEventListener('click', function(e) {
   applyState.call(this,e.ctrlKey);
});

document.addEventListener('keyup', function(e) {
    console.dir(e);
    if (e.keyIdentifier.toLowerCase() == 'right')
    {
        applyState.call(o,e.ctrlKey);
    }
});