Fixed scrolling sidebar

gistfile1.js

// Keeps the order recap box fixed on scroll, a la Apple Store
// http://jqueryfordesigners.com/fixed-floating-elements
$(function () {

  var msie6 = $.browser == 'msie' && $.browser.version < 7;

  if (!msie6 && $('#sidebar').length > 0 && false) {
    var top = $('#logo').offset().top - parseFloat($('#sidebar').css('marginTop').replace(/auto/, 0)),
    order_recap_height =  $('#sidebar').height(),
    order_form_wrapper_height = $('#main-content').height();
    order_form_container_height = $('.main-container').height();

    $(window).scroll(function (event) {
      // what the y position of the scroll is
      var y = $(this).scrollTop();

      if (order_recap_height >= order_form_wrapper_height) {
        $('.main-container').height(order_recap_height);
      }
      // whether that's below the form
      if (y >= top && $(window).height() >= order_recap_height) {
        // if so, ad the fixed class
        $('#sidebar').addClass('fixed');
        $('#logo').addClass('fixed');
        $('#header-nav').addClass('fixed-logo');
        $('#main-content').addClass('fixed-sidebar');
      } else {
        // otherwise remove it
        $('#sidebar').removeClass('fixed');
        $('#logo').removeClass('fixed');
        $('#header-nav').removeClass('fixed-logo');
        $('#main-content').removeClass('fixed-sidebar');
      }
    });
  }
});