anchor.diff:      function check_course_conflict(data) {
           for (var row = data['start']; row <= data['end']; row++) {
               var cur = $('.row' + row + '.col' + data['col']);
  -            if (cur.attr('alt') != '' && cur.text().trim() !='')
  +            if (cur.attr('alt') != '' && cur.text().trim() != '')
                   return {
                       'name': cur.text().trim(),
                       'time': data['orign_time']
  
positive.code:               </div>
                <hr>
                <%= render 'courses/course_list' %>
            <% end %>
          </div>
        </div>
      </div>
    </div>
  </div>
  
  <% if logged_in? and @in_course_select_time %>
      <%= render 'courses/curriculum_table' %>
  
negative.code: <% if @in_course_select_time %>
      <div class="container-fluid">
        <div class="row">
          <div class="col-sm-12">
            <div class="panel panel-primary table_border">
              <div class="panel-heading table_new">
                <h3 class="panel-title">
                  <%= student_logged_in? ? "选修课程" : "已开放的课程列表" %>
                </h3>
              </div>
              <div class="panel-body" style="min-height: 450px">
                <div class="row">
                  <%= form_tag("/courses/list", method: "post") do %>
                      <div class="form-group">
  