[udoprog]

Side note: Firefox extensions aren't native code, they're written in JS.

EDIT: I do however agree that chrome is more well designed. Firefox has been through a lot of iterations through the years.

[mnutt]

While most Firefox extensions are in JS, I believe you can bind to native c++ as well.

[lmz]

Chrome also allows you to access native code in extensions using NPAPI plugins: http://code.google.com/chrome/extensions/npapi.html