print html receipt with auto height

I am creating a html page and print it as receipt that is 75mm width and height 100mm. But I would like to make it to be auto height to fit my content. Please kindly help.

<?php
    $qrString = $_GET['qrString'];
    $tableNumber = $_GET['tableNumber'];
?>

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>receipt</title>
  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/normalize/3.0.3/normalize.css">
  <link rel="stylesheet" href="../paper.css">
  <style>
    @page { size: 75mm 100mm } /* output size */
    body.receipt .sheet { width: 58mm; height: 100mm } /* sheet size */
    @media print { body.receipt { width: 58mm } } /* fix for Chrome */
  </style>

  <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>

</head>

<body class="receipt">
  <section class="sheet padding-10mm">
        <?php echo '<h1>檯號: '.$tableNumber. '</h1><br><br>' ?>


      <img id='barcode' 
            src=<?php echo 'https://api.qrserver.com/v1/create-qr-code/?data=' .$qrString. '&amp;size=300x300' ?>
            alt="" 
            title="HELLO" 
            width="300" 
            height="300" />
  </section>
</body>

<script type="text/javascript">
<!--
window.print();
</script>
</html>