reactjs Cannot read property 'keys' of undefined

Edit: oddly, after our comments above, I checked to see if it was indeed the babel core version, I am using this one in my fiddle:

https://cdnjs.cloudflare.com/ajax/libs/babel-core/5.8.24/browser.js

The second I switch to your version above I get this:

Uncaught TypeError: Cannot read property 'keys' of undefined

Use React.createClass not ReactDOM.createClass and wrap multiple lines of html in parenthesis like so:

Working Example: https://jsfiddle.net/69z2wepo/38998/

var Hello = React.createClass({  render: function() {    return (            <div>        <h1>Hello World</h1>        <p>This is some text</p>       </div>    )  }});ReactDOM.render(  <Hello name="World" />,  document.getElementById('container'));

Just to be clear, as the other answers are a bit convoluted. The problem was using "babel-core" instead of "babel-standalone". Just look up for a cdn for babel-standalone instead.

https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.26.0/babel.js

Today is my first day with React, and I've faced this issue when I tried to use Babel to transpile the JSX!

The issue is the version you are trying to use, please use this one instead:

<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.25.0/babel.min.js"></script>

Don't forget to write type="text/babel" in the <script> tag which you will write the JSX in to let Babel transpile it for you, if you don't, you will find this error (As I have faced it too! :D):

Uncaught SyntaxError: Unexpected token <