This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Frames are a client side phenomenon. To the server, they're different webpages generated from different requests. You'll either need to store the value in a session scoped variable or use client side coding to pass the value between frames.