jitsi-meet/react/features/always-on-top/index.js

import React from 'react';
import ReactDOM from 'react-dom';

import AlwaysOnTop from './AlwaysOnTop';

// Render the main/root Component.
ReactDOM.render(
    <AlwaysOnTop />,
    document.getElementById('react')
);

window.addEventListener('beforeunload', () => {
    ReactDOM.unmountComponentAtNode(document.getElementById('react'));
});