CODE EXAMPLE FOR JAVASCRIPT

firebase recaptcha using react js

class App extends Component {
  componentDidMount() {
    const reCaptchaVerifier = new firebase.auth.RecaptchaVerifier('sign-in-button', {
      size: 'invisible',
      callback: function (response) {
        console.log('It works!');
      },
    });
    reCaptchaVerifier.render();
  }

  render() {
    return (
      <form>
        <input />
        <button id="sign-in-button">Submit</button>
      </form>
    );
  }

}