yes you can but it will be exhaustive.here is a skeleton -
document.onkeydown = function(evt)
{
evt = evt || window.event;
if (evt.keyCode == 37)
{
}
else if (evt.keyCode == 38)
{
}
else if (evt.keyCode == 39)
{
}
else if (evt.keyCode == 40)
{
}
};
and there is lots of thirdpart tools to acheive this task like superfish, Suckerfish Dropdowns .
http://www.adipalaz.com/experiments/css/accessible_ddmenu_test.html[
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