Google Analytics Track Scroll End
(function($){
var $window = $(window),
$document = $(document),
scrollEnd = function(){
if(($window.height() + $window.scrollTop() + 20) >= $document.height()){
ga("send", "event", "scroll", document.location.pathname, "100%");
$window.off("scroll", scrollEnd);
}
};
$window.on("scroll", scrollEnd);
})(jQuery);