Any way to split a window inside a browser to display 2 sites?:shrug:

You can shrink each site to occupy half of the screen space by putting the cursor on a frame edge (should see arrow with two heads) left click (hold) and pull toward the center.

use a chain saw and duct tape. :)

you can open 2 instances of the browser in question and resize them.
in firefox this only works if you have tabbed browsing disabled.