Stop window scroll with keycode (arrows), event.preventDefault() not working?

Question

I built an autosuggest, and keycode works to navigate up and down through the list, but it scrolls the window. I have tried event.preventDefault() but it is not stopping it. Any ideas? This is what I have tried:

$(document).keyup(function(e) {
e.returnValue=false;
e.preventDefault();
switch(e.keyCode) {
    case 40:
        suggestionLine++;
                $('#suggestionLine_'+suggestionLine).focus();
                break;
// etc...

Thank you!

Answer 1

You need keydown, not keyup.

Why? The default operation that you're trying to prevent happens immediately when you press the key (try it now!). This allows for things like autorepeat, which will send multiple keydown events before sending a single keyup event. By the time keyup is fired, the scrolling has already taken place.