is it possible to read from a text file in javascript? or to include a text file onto a page? (like include($filename) in php)
if not, can it be done without using php (or frames )?

Basically No!

You could make an external script of lines of document.write() lines.

What about SSI ?

well thats not good. i can't use ssi (not in this particular project anyway). i have thought of the document.write();s but that would eliminate any hope for creating a non-js requiring site without actually duplicating code. oh well... it was worth a try