Hello reader's! If you are making the website based on user press key events. Then to detect the arrow key pressed by user we can code as below:-

document.onkeydown = function(e) {
    switch (e.keyCode) {
        case 37:
            alert('You just press Left key');//Left arrow key is pressed
            break;
        case 38:
            alert('You just press Up key');//Up arrow key is pressed
            break;
        case 39:
            alert('You just press Right key'); //right arrow key is pressed
            break;
        case 40:
            alert('You just press Down key'); //Down arrow key is pressed
            break;
    }
};

The output will be an alert box saying 'Left arrow key is pressed'