title: What is a reverse line feed
body: <p>Actually, I googled for a while but without a success. It's just too abstract for me. Anyway, My English is broken.
    What I want to know is two points as below:
         What is a reverse line feed?
         What is the difference between reverse line feed and line feed?
    So, is there anyone can give me an example or make an explanation? Thank you very much.
  PS: I'm an invoice here. I don't know whether I made it clear or not for you.</p>