React

HTML

<script>
window.test = function() {
	console.log('loading...');
}
</script>


<input type="button" onclick="js:window.test();" value="click me"/>
<div id="app" var1="test"></div>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#app {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  transition: all 0.2s;
}

li {
  margin: 8px 0;
}

h2 {
  font-weight: bold;
  margin-bottom: 15px;
}

.done {
  color: rgba(0, 0, 0, 0.3);
  text-decoration: line-through;
}

input {
  margin-right: 5px;
}

React

class TodoApp extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
    	test: '',
    	items: [
      	{ text: "Learn JavaScript", done: false },
        { text: "Learn React", done: false },
        { text: "Play around in JSFiddle", done: true },
        { text: "Build something awesome", done: true }
      ]
    }
  }
  
  componentDidMount = () => {
  	window.test = this.test;
  }
  
  test = () => {
  	this.setState({
    	...this.state, test: Math.random()
    });
  }
  
  render() {
    return (
      <div>
        <h2>Todos:</h2>
        <ol>
        {this.state.items.map(item => (
          <li key={item.id}>
            <label>
              <input type="checkbox" disabled readOnly checked={item.done} /> 
              <span className={item.done ? "done" : ""}>{item.text}</span>
            </label>
          </li>
        ))}
        </ol>
        <p>{this.state.test}</p>
      </div>
    )
  }
}

ReactDOM.render(<TodoApp />, document.querySelector("#app"))