Active Scroll

active.js

    var sections = $('section'),
      links = $('nav ul li a'),
      lis = $('nav ul > li');

    $(window).scroll(function() {
      var currentPosition = $(this).scrollTop();
      links.removeClass('active');
      lis.removeClass('active');

      sections.each(function() {
        var top = $(this).offset().top,
          bottom = top + $(this).height();

        if (currentPosition >= top && currentPosition <= bottom) {
          var link = $('a[href="#' + this.id + '"]');
          link.addClass('active-color');
          link.parent().addClass('active');
        } else {
          link = $('a[href="#' + this.id + '"]');
          link.removeClass('active-color');
          link.parent().removeClass('active');
        }

      });

    });