Viewing a Document with WebViewer Server

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

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

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