//menu
$('.menu img').hover(function() {
$(this).stop(true, false).animate({opacity: 0}, {duration: 200})}, function() {
$(this).stop(true, false).animate({opacity: 1}, {duration: 500})
});

$('.menu span').mousedown(function() {
$(this).stop(true, false).animate({opacity: 0}, {duration: 0})}, function() {
$(this).stop(true, false).animate({opacity: 1}, {duration: 500})
});