<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>PDF Test</title>
</head>
<body>
  <h2>View PDF</h2>
  <button onclick="document.getElementById('pdfFrame').style.display='block'">
    Show PDF
  </button>

  <div id="pdfFrame" style="display:none; margin-top:20px;">
    <iframe src="sample.pdf" width="100%" height="600px" style="border:none;"></iframe>
  </div>
</body>
</html>