I have embedded my web game, but when the user presses the spacebar, the entire page scrolls. The alt key also doesn't not prevent default properly.

I have this on my game:

document.addEventListener('keyup', e => {         
    e.preventDefault();         
    e.stopPropagation();         
    e.stopImmediatePropagation();         
    handleInput(e);         
    return false;     
});

But it does nothing and the page still scrolls down. Please to help.

Figured it out, turns out you need to do it on keydown as well:

window.addEventListener('keydown', e => e.preventDefault());
window.addEventListener('keyup', e => e.preventDefault());