Wrapping text in windowed browser

Sometimes I want two side-by-side browser windows; for example, so I can compare two recipes, or have a video open and a website. Occasionally the text will play nice and “wrap” so I can read it easily. The StraightDope does this, unless typing in a box (as I am currently doing). But, for example, Chowhound.chow.com does not. I have to scroll left and right for each line.

So, is there any way to force the kind of wrapping I want–maybe with a Firefox extension–or is it simply governed by the site’s coding?

Bonus–I have a similar problem on mobile browsing, except I’m not trying to do windowed browser, I just (on many sites) have to keep scrolling around once I’ve zoomed in to where my old eyes can read it.