test-portrait.html

<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <title>Portrait Testing</title>
  <style>
    body { margin: 20px 0 0 20px; font-family: sans-serif; overflow-x: scroll; background: #bfbfbf}
    .wrapper { width: 8000px; }
    iframe { margin: 0 20px 20px 0; float: left; border: none; background: #fff; box-shadow: #aaa 2px 4px 6px}
    iframe::-webkit-scrollbar {display: none;}  
  </style>  
</head>
<body>
  <div class="wrapper">
    <iframe src="./" sandbox="allow-same-origin allow-forms" seamless width="320" height="480"></iframe>
    <iframe src="./" sandbox="allow-same-origin allow-forms" seamless width="480" height="800"></iframe>
    <iframe src="./" sandbox="allow-same-origin allow-forms" seamless width="600" height="1024"></iframe>
    <iframe src="./" sandbox="allow-same-origin allow-forms" seamless width="768" height="1024"></iframe>
  </div>
</body>
</html>