index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1.0 maximum-scale=1.0"/>
    <link rel="icon" href="./assets/favicon.ico" sizes="32x32" type="image/vnd.microsoft.icon">
    <title class="application-title"></title>
    <!-- SURVEY123 JS API -->
    <script src="https://survey123.arcgis.com/api/jsapi"></script>
    <!-- APPLICATION -->
    <link rel="stylesheet" type="text/css" href="./css/application.css">
    <script type="module" src="./js/Application.js"></script>
  </head>
  <body>
    <div id="main-section">
      <div id="survey123-panel" class="panel"></div>
      <div id="ookla-panel" class="panel hide">
        <iframe id="ookla-container" frameborder="0"></iframe>
      </div>
    </div>
  </body>
</html>