//1. get the command-line tool:
$ npm install -g babel

//2. then watch the jsx file example.js to transform and move to build/example.js
$ babel example.js --out-dir=build

//3. advanced: watch all the jsx tranform in src/ folder and move to build/ folder dynamically.
$ babel src/ --watch --out-dir build/

//4. alternative: in react-0.14.0 basic-commonjs/ folder:
$ npm install
$ ./node_modules/.bin/watchify index.js -v -t babelify -o bundle.js
// to generate bundle.js which combines react, react-dom and index.js

//1. get browser.js:
$ npm install babel-core

//2. then:
<script src="react/build/react.js"></script>
<script src="babel/browser.js"></script>

//3. add text/babel type:
<script type="text/babel">
  React.render(
    jsx-stuff,
    document.getElementById('app')
  );
</script>