http://www.gnu.org/software/emacs/emacs-lisp-intro/html_mono/emacs-lisp-intro.html

auto file mode is nice, it is really what I should have, now I am in auto-fill-mode an doing a test, it turns out beaufilly, the looking of the page is no longer messy as before, and it is a minor mode, I can simply add (auto-fill-mode) in my .emacs to achieve this without bad effect on other functions.