demo.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="https://unpkg.com/openlayers/dist/ol.css">
    <link rel="stylesheet" href="https://unpkg.com/ol-popup@2.0.0/src/ol-popup.css">
    <link rel="stylesheet" href="https://unpkg.com/ol-geocoder/dist/ol-geocoder.min.css">
  </head>
  <body>
    <div>---- geocoder ----</div>
    <div id="target"></div>
    <div>---- log ----</div>
    <div id="log"></div>

    <script src="https://unpkg.com/openlayers@4.4.2"></script>
    <script src="https://unpkg.com/ol-popup@2.0.0"></script>
    <script src="https://unpkg.com/ol-geocoder"></script>

    <script src="https://unpkg.com/jquery@3.3.1"></script>
    <script src="https://unpkg.com/dat-gui-defaults@1.0.0"></script>
    <script src="./demo.js"></script>
  </body>
</html>