test3.html

<!DOCTYPE html>
<html>
<head>
  <title>Create a Map</title>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  <meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
  <link rel="stylesheet" href="http://js.arcgis.com/3.8/js/dojo/dijit/themes/claro/claro.css">
  <link rel="stylesheet" href="http://js.arcgis.com/3.8/js/esri/css/esri.css">
  <style>
    html, body, #mapDiv{
      padding: 0;
      margin: 0;
      height: 100%;
    }
  </style>
  
  <script src="http://js.arcgis.com/3.8/"></script>
  <script>
    require([
      "esri/map",
      "esri/dijit/Directions",
      "esri/layout",
      "dojo/domReady!"
    ], function (Map, Directions, Layout) {
    // code goes here
    });
  </script>

</head>
<body class="claro">
  <div id="mapDiv"></div>
</body>
</html>