班级添加学生时先输入名字再取消，然后再点开添加学生输入刚刚的名字，没有搜索结果

app/views/courses/search_not_students.js.erb

@@ -1,6 +1,7 @@
 <% if params[:is_observe] %>
 $("#search_not_students_list").html("<%= j(render :partial => 'courses/settings/search_not_students_list') %>");
 <% else %>
+laststSearchCondition = '';
 var htmlvalue = "<%= j(render :partial => 'courses/settings/add_students') %>";
 pop_box_new(htmlvalue, 440, 490);
 <% end %>