How can I read ‘native code’ JavaScript functions?

Question

Is there any way to see the declaration of JavaScript native code? Whenever I try to look at a native function in Chrome or Firefox, it says "native code":

> String.fromCharCode function fromCharCode() { [native code] } 

What does this mean, and is there any tool which can help me to read actual code?

Answer 1

The reason Chrome or Firefox says that the code is native is that it really is native - the WebKit and Firefox developers have coded up that functionality in C or C++, not JavaScript. However, if you want to see the actual code, you can look at the source repositories for Chromium and Firefox.

Answer 2

Not within the JavaScript environment, but you can view the source for the open-source implementations.

Google V8: http://code.google.com/p/v8/source/browse

Mozilla SpiderMonkey: https://developer.mozilla.org/en/SpiderMonkey