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HTML Settings

Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

              <div id="app-root"></div>
<div id="modal-root"></div>

              #modal-root {
  position: relative;
  z-index: 999;

.app {
  height: 10em;
  width: 10em;
  background: lightblue;
  overflow: hidden;

.modal {
  background-color: rgba(0,0,0,0.5);
  position: fixed;
  height: 100%;
  width: 100%;
  top: 0;
  left: 0;
  display: flex;
  align-items: center;
  justify-content: center;

              // These two containers are siblings in the DOM
const appRoot = document.getElementById('app-root');
const modalRoot = document.getElementById('modal-root');

// Let's create a Modal component that is an abstraction around
// the portal API.
class Modal extends React.Component {
  constructor(props) {
    // Create a div that we'll render the modal into. Because each
    // Modal component has its own element, we can render multiple
    // modal components into the modal container.
    this.el = document.createElement('div');

  componentDidMount() {
    // Append the element into the DOM on mount. We'll render
    // into the modal container element (see the HTML tab).

  componentWillUnmount() {
    // Remove the element from the DOM when we unmount
  render() {
    // Use a portal to render the children into the element
    return ReactDOM.createPortal(
      // Any valid React child: JSX, strings, arrays, etc.
      // A DOM element

// The Modal component is a normal React component, so we can
// render it wherever we like without needing to know that it's
// implemented with portals.
class App extends React.Component {
  constructor(props) {
    this.state = {showModal: false};
    this.handleShow = this.handleShow.bind(this);
    this.handleHide = this.handleHide.bind(this);

  handleShow() {
    this.setState({showModal: true});
  handleHide() {
    this.setState({showModal: false});

  render() {
    // Show a Modal on click.
    // (In a real app, don't forget to use ARIA attributes
    // for accessibility!)
    const modal = this.state.showModal ? (
        <div className="modal">
            With a portal, we can render content into a different
            part of the DOM, as if it were any other React child.
          This is being rendered inside the #modal-container div.
          <button onClick={this.handleHide}>Hide modal</button>
    ) : null;

    return (
      <div className="app">
        This div has overflow: hidden.
        <button onClick={this.handleShow}>Show modal</button>

ReactDOM.render(<App />, appRoot);

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