php question... opening external page/writing to it...

Hey... A quick question... How can I do the following.... (I know it's simple..!!!) All from the same page... Do some processing... Open an external page Write some stuff to the external page... The issue I seem to have is that if I open the external page during the onload... it's not ready when I want to write the data.... Any hints/comments/samples.... Thanks... Bruce bedouglas@earthlink.net