How do browser emulators work?

A lot of you have probably seen browser emulators that allow you to look at your web page in the way that (insert browser in question) renders it. Tools like Browserlab from Adobe and BrowserCam.com are used to test browsers and devices for rendering glitches.

I checked out the response and links for emulating game systems: How do emulators work and how are they written?

I'm interested in specifically, how web browsers render content - where the "rules" for how elements are ren开发者_JAVA百科dered are defined.

Does anyone know of any resources that discuss this? I'm not looking for tools - I use those already - I want to know how they work.

I don't think emulators are in the picture with browsers. The products you mention probably use actual browser implementations.

Webkit is the open source engine behind Chrome, Safari and numerous other implementations including Adobe AIR so I'd recommend you start there if you're interested.

To answer your question about the rules, these are defined by w3.org

The way those browser "emulators" are implemented is probably actual web rendering engines that render to a bitmap instead of your screen. webkit2png will do that for you with the WebKit engine, for other engines, you can do something similar.