<% if is_praise_homework User.current.id,homework.id  %>
  <%= link_to "",praise_homework_homework_attach_path(homework),
              :class => "wzan_img", :remote => true, :title => "点赞"%>
<% else %>
  <a class="wzan_img wzan_visited"  title="您已经赞过该作业"></a>
<% end %>
<a>
  <%= praise_homework_count homework.id  %>
</a>