The XML syntax inside of JavaScript is called JSX; check out the [JSX syntax](/react/docs/jsx-in-depth.html) to learn more about it. In order to translate it to vanilla JavaScript we use `<script type="text/jsx">` and include `JSXTransformer.js` to actually perform the transformation in the browser.
> The comment parser is very strict right now, in order for it to pick up the `@jsx` modifier, two conditions are required. The `@jsx` comment block must be the first comment on the file. The comment must start with `/**` (`/*` and `//` will not work). If the parser can't find the `@jsx` comment, it will output the file without transforming it.
If you want to use React within a module system, [fork our repo](http://github.com/facebook/react), `npm install` and run `grunt`. A nice set of CommonJS modules will be generated. Our `jsx` build tool can be integrated into most packaging systems (not just CommonJS) quite easily.