Sticky side bar JS

Sticky Side Bar

  var $sidebar   = $('#sidebar'),
      $window    = $(window),
      offset     = $sidebar.offset(),
      topPadding = 0;

  $window.scroll(function() {
    if ($window.scrollTop() > offset.top)
    {
      $('#sidebar').removeClass('checkout-sidebar');
      $('#sidebar').addClass('checkout-sidebar-fixed');
    }
    else
    {
      $('#sidebar').removeClass('checkout-sidebar-fixed');
      $('#sidebar').addClass('checkout-sidebar');
    }
  });