<div class="container">
    {% from "_formhelper.html" import render_field %}
    <form id="upload-form" method="POST" action="/sixth_form/" enctype="multipart/form-data">
    <dl>
      {{render_field(form.stu_name)}}
        </dl>
        <p>Student Signature</p>
<div class="wrapper">
  <img src="{{ url_for('static', filename='images/grey.jpeg') }}" width=400 height=200 />
  <canvas id="signature-pad" class="signature-pad" width=400 height=200></canvas>
</div>
<div>
  <button id="clear" type="Button">Clear</button>
</div>
<br>
    <p><input id="finalsub" type="submit" value="Submit"></p>
    </form>
</div>

<script>
var signaturePad = new SignaturePad(document.getElementById('signature-pad'), {
  backgroundColor: 'rgba(255, 255, 255, 0)',
  penColor: 'rgb(0, 0, 0)'
});
var saveButton = document.getElementById('finalsub');
var cancelButton = document.getElementById('clear');

saveButton.addEventListener('click', function (event) {
  var data = signaturePad.toDataURL('image/png');

// Send data to server instead...
  window.open(data);
});

cancelButton.addEventListener('click', function (event) {
  signaturePad.clear();
});
</script>