Not only that, but you may want to brush up on what Javascript is.
Just because you write GWT code in Java, it's still Javascript in the
end. If you figure out a way to maintain session state purely on the
client-side (especially through Javascript only) between pages I'd
like to hear about it. Cause that would be a huge security & privacy
flaw in the browser.
One hack, that may or may not work, would be to have p1 & p2 include
p3.html as an iframe. P3 then maintains "state" through cookies which
hopefully haven't been cleared in the transition.
The other, proper way, would be to have p3 (your actual app) load p1
in an iframe. then when a request is made, load p2. However, you're
going to have XSS issues - AFAIK, this kind of stuff of scripts
communicating between different pages is an HTML5 "feature".