JSFiddle - React, Tailwind, and code Playground

HTML

<div>Non main content</div>
<div id="main_content">Main content</div>

JavaScript

$(document).ready(function () {
        $("#main_content").mouseover(armKeyEvent);
        $("#main_content").mouseout(shutdownKeyEvent);
        
        /* The only purpose of this instruction is to give focus 
            to the results frame in jsFiddle ; 
            don't use it in a normal page ! */
        $(window).focus();
        
        function armKeyEvent() {
            $(window).keydown(function(e) {
                if(e.which == 40) {
                    alert("button Down");
                    return false;
                }
            });
        }
        
        function shutdownKeyEvent() {
            $(window).unbind('keydown');
        }
    });