So I prowl the web a lot and occasionally find myself with a bunch of open tabs. Sometimes I want to be able to compare contents in the two tabs - say two lists of all-time best movies to see what one list leaves out.
Use the Split Panel add-on for Firefox or Frame Two Pages for Chrome. In Firefox, all you need to do is right click on your page, choose Split and then decide Left, Right or Bottom. Then in the new pane choose the tab you want to compare from your open tabs.
In Chrome, click on the tab you want with the other tab you want just to the left. Then click on the Frame Two Pages icon at top right .
Ernster, the Virtual Library Cat