Making a vertically equal partition on a Centralized Webpage, without using Frames and Table concept ?

I'm trying to make a vertical split in a centralized webpage. I'm doing the split with the concepts of frames and tables but its not satisfying my expectation.

I tried using div for separation but found it difficult to mange and running into conflict. I google for solution but not find anything related. I'll be sorry if it is very basic. Any help and suggestions would greatly appreciated.

Thanking in Advance, Regards...