Поместите сгенерированный JSPDF PDF-файл в iframe

var generatePdfFromHtml = function(pdf, html, callback) {
  console.info("Generating Pdf");
  pdf.html(html, {
    'callback': function(pdf) {
      if (callback && typeof callback === 'function') {
        console.info("Offering Pdf as callback");
        callback(pdf);
      }
    }
  });
}

$(document).ready(function() {

  /**
   * @var {jsPDF} pdf
   */
  var pdf = new jsPDF('p', 'pt', 'a4');

  $("#myform").on('submit', function(e) {
    e.preventDefault();
    var val = $("#inputData").val();
    /* Dummy Html to emulate the situation I am */
    val = "<b>" + val + "</b>";
    generatePdfFromHtml(pdf, val, function(returnedPDF) {
      console.info("Generated Pdf");
      var blob = pdfFromCallback.output('blob');
      /* Write Pdf into #display Iframe */
      var blob_url = URL.createObjectURL(blob);
      var iframeElementContainer = document.getElementById('display');
      iframeElementContainer.src=blob_url;
    });
  });

});

<script src = "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src = "https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.5.3/jspdf.debug.js" integrity = "sha384-NaWTHo/8YCBYJ59830LTz/P4aQZK1sS0SneOgAvhsIl3zBu8r9RevNg5lHCHAuQ/" crossorigin = "anonymous"></script>
<script src = "https://html2canvas.hertzen.com/dist/html2canvas.min.js"></script>
<script src = "https://cdnjs.cloudflare.com/ajax/libs/pdf.js/2.2.2/pdf.js"></script>

<form id = "myform">
  <input id = "inputData" name = "metallica" placeholder = "Enter a metallica song"><button type = "submit">Enter Sandman</button>
</form>

<iframe id = "display" style = "width:100%; height:100%; overflow:scroll;"></iframe>