JSFiddle - React, Tailwind, and code Playground

by Allendar

JavaScript

window.keyHoldDown = false;

document.body.addEventListener('keydown', function(e) {
    if (e.keyCode == '17' || e.keyCode == '18') {
        window.keyHoldDown = e.keyCode;
    }
}, false);

document.body.addEventListener('keyup', function(e) {
    e.preventDefault();
    // CTRL
    if (window.keyHoldDown == '17' && e.keyCode != '17') {
        document.body.innerHTML = 'CTRL + ' + e.keyCode;
    }
    // ALT
    else if (window.keyHoldDown == '18' && e.keyCode != '18') {
        document.body.innerHTML = 'ALT + ' + e.keyCode;
    }
    
    if (e.keyCode == '17' || e.keyCode == '18') {
        window.keyHoldDown = false;
    }
}, false);