Scroll thingy

scrollerific.js

// Container element to add/remove class to
var container = $('body')

// this is the class that will be added to the body tag when the page is scrolled down
var scrollClass = "window-scrolled";

// how far down the page needs to be scrolled for the class to be added
var positionTrigger = 10;

$(window).scroll(function (event) {
    // how far down the page is currently scrolled
    var scroll = $(window).scrollTop();

    // if we're farther down than our trigger, add the class
    if (scroll > positionTrigger) {
      container.addClass(scrollClass);
    } else {
      container.removeClass(scrollClass);
    }
});