is there a way to run gwt on a proxy loaded web page ?

ex) using proxy script on myexamplesite.com that loads finance.google.com, and running GWT on the newly loaded page.

I've been doing the above before I found about GWT, using LAMP stack + Jquery (UI), which quickly turned out to be crap and inefficient. All this trouble to bypass browser's default Single Origin Policy.

So, right now, is it possible to overcome this problem with GWT ? Is it possible to some how, run javascript on a html page from finance.google.com loaded into myexamplesite.com's frame with GWT or other solution?

I am not looking to do JSON or RSS related topics. What I need is high lighted in bold. Is GWT + Gears what I should be using ?

Thank you.