React Js String Substr Method

<!DOCTYPE html>
<html>

function App() {
          const myString = 'Hello, World!';
            const substring = myString.substr(-6); // Extracts 'World!' by counting from the end of the string

return (
                <div className='container'>
                    <h3>React Js String Substring Method</h3>
                    <p>Strin: <span>{myString}</span></p>
                    <p>substring: {substring}</p>
                </div>
            );
        }

ReactDOM.render(<App />, document.getElementById('app'));
    </script>
    <style>
        .container {
            text-align: center;
            box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.12), 0 2px 4px 0 rgba(0, 0, 0, 0.24);
            width: 600px;
            margin: 0 auto;
            padding: 20px
        }

h3 {
            color: #333;
            font-size: 24px;
            margin-bottom: 10px;
        }

p {
            color: #555;
            font-size: 16px;
            margin-bottom: 5px;
        }

span {
            font-weight: bold;
            color: #007bff;
        }
    </style>
</body>

</html>