Viewing a Document with WebViewer Server

WebViewer(
  {
    path: '../../../lib',
    webviewerServerURL: 'https://demo.pdftron.com/',
    initialDoc: 'https://pdftron.s3.amazonaws.com/downloads/pl/demo-annotated.pdf',
  },
  document.getElementById('viewer')
).then(instance => {
  samplesSetup(instance);
  document.getElementById('select').onchange = e => {
    instance.UI.loadDocument(e.target.value);
  };

  document.getElementById('file-picker').onchange = e => {
    const file = e.target.files[0];
    if (file) {
      instance.UI.loadDocument(file);
    }
  };

  document.getElementById('url-form').onsubmit = e => {
    e.preventDefault();
    instance.UI.loadDocument(document.getElementById('url').value);
  };
});