JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" name="foo" id="foo" />

<input type="text" name="bar" id="bar" />Some text.

JavaScript

document.getElementById('foo').onkeydown = function(e) {
    e = e || window.event;
//alert(e.keyCode);
    switch( e.keyCode || e.which) {
        case 70: // F key
        case 65: // A key
            if( e.ctrlKey) {
            return false;
            }
    }
}