<html>
<body>
    <div id="root"></div>
    <script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
    <script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>
    <script type="text/babel">

    class StopWatch extends React.Component {
        state = {lapse: 0, running: false}
        handleRunClick = () => {
            this.setState(state => {
           