Change opacity on scroll: http://codepen.io/michaeldoyle/pen/Bhsif
var header = $('.desktop #header');
var range = 350;
$(window).on('scroll', function () {
var st = $(this).scrollTop();
header.each(function () {
var offset = $(this).offset().top;
var height = $(this).outerHeight();
offset = offset + height / 2;
$(this).css({ 'opacity': 1 - (st - offset + range) / range });
});
});