There is a Google extension that can help you achieve the mission of splitting the webpage into two screens.
Google Chrome users may install the “Frame two pages” extension for Google Chrome Browser from the website.This extension has been helpful while I was trying to compare two wireless routers. You may select the split screen in rows or columns and thus make your selection easier.This gadget may be helpful if you are e.g. translating one page to another page or otherwise editing a text, using two windows.
*Warnings*
Don't test the extension on this gallery of extensions or other "https" pages. Use ordinary "http" pages only; the "scheme" has to agree. Also, some pages such as "TraceMyIP.org" deliberately use a "framekiller" to jump out of the frames; I know of no way how to overwrite their stubborn opinions.