Modify Google Chrome or Mozilla Firefox display settings

I would like to know if it is possible to modify Chrome or 开发者_C百科Firefox display settings, so that it would only show rectangles of HTML DOM objects? What I want to do is to decrease rendering engine job amount as much as possible, so it would only build layout of the page.

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People usually refer to this mode of operation as "headless" (i.e. without UI).

Usually there's an additional requirement - to be able to run it server-side without the usual for client software installed. If you're running it client-side, I wouldn't bother about optimization, it shouldn't give you a big win anyway.

Otherwise, try searching using that term. I've seen it asked for several times, but haven't seen a working out-of-box solution.

[edit] just saw http://hg.mozilla.org/incubator/offscreen, which seems to be a headless version of Mozilla.

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I wouldn't go as low-level as modifying the renderer. Instead, I suggest you use Firefox's Greasemonkey to replace the elements from the page with whatever it is you need. You'll need to know a bit of JavaScript, but it's not that hard.

However, this will only work on client side. If you want to do this on server-side ( so that it will work on any page a user requests through your own ), my guess is you'll need to grab the page's content in a string, and then modify it using a HTML parser.