We provide CDN-hosted versions of React [on our download page](/react/downloads.html). These pre-built files use the UMD module format. Dropping them in with a simple `<script>` tag will inject the `React` and `ReactDOM` globals into your environment. It should also work out-of-the-box in CommonJS and AMD environments.
## Using React from npm
You can use React with a CommonJS module system like [browserify](http://browserify.org/) or [webpack](https://webpack.github.io/). Use the [`react`](https://www.npmjs.com/package/react) and [`react-dom`](https://www.npmjs.com/package/react-dom) npm packages.
```js
// main.js
var React = require('react');
var ReactDOM = require('react-dom');
ReactDOM.render(
<h1>Hello, world!</h1>,
document.getElementById('example')
);
```
Configure [babel](https://babeljs.io/) with a `.babelrc` file:
```json
{ "presets": ["react"] }
```
> Note:
>
> If you are using ES2015, you will want to also use the `babel-preset-es2015` package.
To install React DOM and build your bundle with browserify:
> If you are using ES2015, you will want to also use the `babel-preset-es2015` package.
**Note:** by default, React will be in development mode, which is slower, and not advised for production. To use React in production mode, set the environment variable `NODE_ENV` to `production` (using envify or webpack's DefinePlugin). For example:
```js
new webpack.DefinePlugin({
"process.env": {
NODE_ENV: JSON.stringify("production")
}
});
```
Update your HTML file as below:
```html{8,12}
<!DOCTYPE html>
<html>
<head>
<metacharset="UTF-8"/>
<title>Hello React!</title>
<scriptsrc="build/react.js"></script>
<scriptsrc="build/react-dom.js"></script>
<!-- No need for Babel! -->
</head>
<body>
<divid="example"></div>
<scriptsrc="build/helloworld.js"></script>
</body>
</html>
```
## Using React from Bower
Bower is a package manager optimized for the front-end development. If multiple packages depend on a package - jQuery for example - Bower will download jQuery just once. This is known as a flat dependency graph and it helps reduce page load. For more info, visit http://bower.io/
