How can I find out the native code of javascript functions?

Question

When I type setInterval into google chrome's developer tools it writes the following to the console

function setInterval() { [native code] }

How can I find out the code that should be in [native code] ?

Answer 1

setInterval() is implemented by the rendering engine.

In Webkit/Blink it's a call to a DOMWindow instance.

The most interesting bits are in DOMTimer.cpp