counter example using classes react without jsx
<script crossorigin src="https://unpkg.com/react@18/umd/react.production.min.js"></script> <script crossorigin src="https://unpkg.com/react-dom@18/umd/react-dom.production.min.js"></script> <div id='root'></div> <script> class Hello extends React.Component { constructor(props) { super(props) this.state = { count: 0 } } render() { return React.createElement('div', null, React.createElement("button",{onClick: () => this.setState({ count: this.state.count + 1})}, "Inc "+ this.state.count)); } } const root = ReactDOM.createRoot(document.getElementById('root')); root.render(React.createElement(Hello, {toWhat: 'World'}, null)); </script>