How to compile in the browser.

babel-browser has been removed.

Use a bundler like browserify/webpack or just require('babel-core').

If you don't want to do it yourself, you can also use babel-standalone which is pre-built and is used in the Try it Out link.

Compiling in the browser has a fairly limited use case, so if you are working on a production site you should be precompiling your scripts server-side. See setup build systems for more information.