cropped/missing text after saving .cnt - file with php

Hello, I want to save a text - which is created in a selfmade javascipt editor - into a .cnt - file with php... It works fantastically if I work in the LAN - environment, but if I work from outside - it's still saving, but it cuts contingent some text...! I can't I understand why it doesn't work, perhaps anyone has an idea?! If there are many spelling mistakes, please excuse me, I'm from Germany and don't speak so much english...! :-)