Saving an external txt file in runtime

i’m trying to find a way to use flash to edit existing .txt files and then save it when its compete… i know it can be done using database’s and some asp or php blah but i was wondering if it was possible to do even just for a local file? any thoughts or sugestions would be greatly apreachiated (even if they’re along the lines of 'no you stupid noob… at least then i know to give up on it :D)