 found in dropdown.less -->
          <li class="dropdown notifications-menu">
            <a href="#" class="dropdown-toggle" data-toggle="dropdown">
              <i class="fa fa-bell-o"></i>
              <span class="label label-warning">10</span>
            </a>
            <ul class="dropdown-menu">
              <li class="header">你有10个通知</li>
              <li>
                <!-- inner menu: contains the actual data -->
                <ul class="menu">
                  <li>
          