main >> features >> handling file uploads

the example should say that, move_uploaded_file is recommend, this make sure it works under restriction mode.

although there's a comment in user note about this, and it also documented in "make_uploaded_file" section.
but remind here will help a lot of ppl, also free a lot of php-helpers :)

btw: there're so many important user note that should be refine to official document, yet i know, document should be keep simple :)