Render Form Error on Dropzone.js, with Django View

I have a page created for File Upload which uses Dropzone.js, and takes data from a Django View. The View for upload is as follows...

def upload_file(request):

    if request.method == 'POST':
        form = UploadFileForm(request.POST, request.FILES)
        if form.is_valid():
            if request.POST.get('case_number'):
                for _file in request.FILES.getlist('file'):
                    extract_properties = get_file_properties(_file)
                    handle_uploaded_file(request.FILES['file'])


                    if extract_properties:

                        for property in extract_properties:
                            print "starting parser"
                            try:
                                property['case_number'] = request.POST.get('case_number')
                                property['evidence_number'] = request.POST.get('evidence_number')
                                result = process_extract(property)

                                if result is None:
                                    print 'Extract Patterns need to be updated OR there exists Processor errors!'

                            except Exception as e:
                                print "!!!!!!!"
                                print "Error, could not upload", e
                                pass

                            #When trying to determine what the header is enable this print statement
                            #print extract_properties

                    else:
                        print 'Unable to identify file uploaded!' 
                return HttpResponseRedirect('')
            else:
                print "NO CASE NUMBER"
        print form
    else:
        form = UploadFileForm()

    file_cleanup('nettop/files/name.csv')

    return render_to_response('nettop/upload_file.html',
                              {'form': form},
                              context_instance=RequestContext(request))

The Template for the UPLOAD FILE uses Dropzone.js, as mentioned. My concern is that when the dropdown selectors for Case_Number or Evidence_Number are left blank, there is no Message Printed to the Browser client. There is a message to the Server console which is as follows:

<tr><th><label for="id_case_number">Case number:</label></th><td><ul     class="errorlist"><li>This field
 is required.</li></ul><select id="id_case_number" name="case_number">
<option value="" selected="selected">---------</option>
<option value="2">1</option>
<option value="1">12</option>
<option value="3">2</option>
<option value="4">3</option>
</select></td></tr>

How can I manipulate this template code below to print that message to my browser?

{% extends "nettop/base.html" %}
{% load staticfiles %}

{% block css %}
{{ block.super }}
<link rel="stylesheet" type="text/css" href="{% static   'nettop/css/dropzone.css' %}" />
{% endblock css %}

{% block page_title %}Upload File{% endblock %}
{% block page_class %}upload-file{% endblock %}
{% block page_id %}upload-file-page{% endblock %}
{% block header_title %}Upload File{% endblock %}
{% block content %}

<!--Be sure to add data-ajax="false" to form to avoid conflict with jQuery Mobile-->
<form id="my-dropzone" class="dropzone" action="{% url "nettop:upload_file" %}" method="post" enctype="multipart/form-data">
  {% csrf_token %}
  {{ form }}
</form>
<button type="submit" id="submit-all" style="visibility: hidden">Submit     Files</button>

<p style="color: red;">
    Please Select a Case & Evidence Number
</p>

{% endblock %}
{% block js %}
{{ block.super }}
<script type="text/javascript" src="{% static    'nettop/js/libs/dropzone.min.js' %}"></script>
<script type="text/javascript">
  Dropzone.options.myDropzone = {
    // Prevents Dropzone from uploading dropped files immediately
    autoProcessQueue : false,
    uploadMultiple: false,
    parallelUploads: 100,
    addRemoveLinks: true,
    maxFiles: 42,
    maxFilesize: 2048,
    //previewsContainer: ".dropzone-previews",
    init : function() {
      var submitButton = document.querySelector("#submit-all");
      myDropzone = this;

      submitButton.addEventListener("click", function(e) {
        // Make sure that the form isn't actually being sent
        e.preventDefault();
        e.stopPropagation();
        // Tell Dropzone to process all queued files
        myDropzone.processQueue();
      });

      // Hide submit button until at least one file has been added
      this.on("addedfile", function() {
        document.getElementById('submit-all').style.visibility = 'visible';
      });

      // TODO: Add success message
      this.on("success", function(file, response){
        if(response.code == 501){ // succeeded
          return file.previewElement.classList.add("dz-success"); // from   source
        }else if (response.code == 403){  //  error
          // below is from the source code too
          var node, _i, _len, _ref, _results;
          var message = response.msg // modify it to your error message
          file.previewElement.classList.add("dz-error");
          _ref = file.previewElement.querySelectorAll("[data-dz-  errormessage]");
          _results = [];
          for (_i = 0, _len = _ref.length; _i < _len; _i++) {
            node = _ref[_i];
            _results.push(node.textContent = message);
          }
          return _results;
         }else{
          return null
        }
      });
  // Listen to the sendingmultiple event. In this case, it's the sendingmultiple event instead
  // of the sending event because uploadMultiple is set to true.
      this.on("sendingmultiple", function() {
    // Gets triggered when the form is actually being sent.
    // Hide the success button or the complete form.
      });

      this.on("successmultiple", function(files, response) {
    // Gets triggered when the files have successfully been sent.
    // Redirect user or notify of success.
      });

      this.on("errormultiple", function(files, response) {
    // Gets triggered when there was an error sending the files.
    // Maybe show form again, and notify user of error
      });
    }
  };
</script>
{% endblock %}