What language is used when developing apps for multiple platforms?

Question

I just caught one of Google's commercials for Chrome where at the end they mention that it runs on Linux, Mac, and PC. So I started wondering how they are able to develop a program that can run on multiple platforms like that? I have experience with Java, and .Net but only on a windows machine. Java is by design portable, but I wouldn't think Google is using Java for something like Chrome where performance is such a concern.

I understand that each version is going to have some platform specific code, such as for the UI. But there must also be some central code that is reused across each platform. What language is this written in?

Answer 1

Here is an entire article about the development of Chrome. It's mostly written in C++.

Answer 2

Chrome is written in C++, so they will have a significant amount of platform-specific code for each OS. They most likely maintain a separate branch for each OS.