Invariant Violation: _registerComponent(...): Target container is not a DOM element

By the time script is executed, document element is not available yet, because script itself is in the head. While it's a valid solution to keep script in head and render on DOMContentLoaded event, it's even better to put your script at the very bottom of the body and render root component to a div before it like this:

<html>
<head>
</head>
<body>
  <div id="root"></div>
  <script src="/bundle.js"></script>
</body>
</html>

and in the bundle.js, call:

React.render(<App />, document.getElementById('root'));

You should always render to a nested div instead of body. Otherwise, all sorts of third-party code (Google Font Loader, browser plugins, whatever) can modify the body DOM node when React doesn't expect it, and cause weird errors that are very hard to trace and debug. Read more about this issue.

The nice thing about putting script at the bottom is that it won't block rendering until script load in case you add React server rendering to your project.

Update: (October 07, 2015 | v0.14)

React.render is deprecated, use ReactDOM.render instead.

Example:

import ReactDOM from 'react-dom';

ReactDOM.render(<App />, document.getElementById('root'));

/index.html

<!doctype html>
<html>
  <head>
    <title>My Application</title>
    <!-- load application bundle asynchronously -->
    <script async src="/app.js"></script>
    <style type="text/css">
      /* pre-rendered critical path CSS (see isomorphic-style-loader) */
    </style>
  </head>
  <body>
    <div id="app">
      <!-- pre-rendered markup of your JavaScript app (see isomorphic apps) -->
    </div>
  </body>
</html>

/app.js

import React from 'react';
import ReactDOM from 'react-dom';
import App from './components/App';

function run() {
  ReactDOM.render(<App />, document.getElementById('app'));
}

const loadedStates = ['complete', 'loaded', 'interactive'];

if (loadedStates.includes(document.readyState) && document.body) {
  run();
} else {
  window.addEventListener('DOMContentLoaded', run, false);
}

(IE9+)

Note: Having <script async src="..."></script> in the header ensures that the browser will start downloading JavaScript bundle before HTML content is loaded.

Source: React Starter Kit, isomorphic-style-loader


the ready function can be used like this: 

$(document).ready(function () {
  React.render(<App />, document.body);
});

If you don't want to use jQuery, you can use the onload function:

<body onload="initReact()">...</body>

Tags:

Javascript

Dom

Reactjs

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