data attr initialization Go to the documentation

The code you need for this:

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Viewer UI demo</title>
    <style>
        body {
          font-family: Arial;
          font-size: 14px;
        }
        #viewer-2d-container {
          position: absolute;
          bottom: 20px;
          left: 20px;
          width: 400px;
          height: 250px;
        }
        #viewer-2d {
          height: 100%;
        }
        #viewer-container {
          position: absolute;
          top: 0;
          bottom: 0;
          width: 60%;
          overflow-y: hidden;
        }
        #viewer {
          height: 100%;
        }
    </style>
  </head>
  <body>
    <div id="viewer-container">
      <div id="viewer">
      </div>
    </div>

    <div id="viewer-2d-container">
      <div id="viewer-2d">
      </div>
    </div>

    <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
    <script src="https://api.bimsync.com/1.0/js/viewer.js"></script>
    <script src="https://api.bimsync.com/1.0/js/viewer2d.js"></script>
    <script type="text/javascript">
      $(function() {
          // 2D Viewer
          var viewer2dUrl = "https://api.bimsync.com/beta/viewer2d/svg?token=eyJ0eXAiOi....";
          var $viewer2d = $('#viewer-2d');

          bimsync.loadViewer2d();

          bimsync.setOnViewer2dLoadCallback(function() {
              $viewer2d.viewer2d('loadUrl', viewer2dUrl);
          });
          
          $viewer2d.bind('loaded', function(event) {
              console.log("2D Viewer loaded!");
          });

          // 3D Viewer
          var viewerUrl = "https://api.bimsync.com/1.0/viewer/access?token=3c2ceca0...";
          var $viewer = $('#viewer');

          bimsync.load(['viewer-ui']);
          
          bimsync.setOnLoadCallback(function() {
              $viewer.viewer('loadUrl', viewerUrl);
              $viewer.viewerUI({
                  enableJoystick: true,
                  joystickHidden: false,
                  enableContextMenu: true,
                  viewer2dId: 'viewer-2d',
                  enableViewer2dIntegration: true,
                  showViewer2dStoreySelect: true,
                  showViewer2dLockedNavigationToggle: true
              });
          });
          
          $viewer.bind('viewer.load', function(event) {
            console.log('Viewer loaded!');
          });

      });
    </script>
  </body>
</html>