django forms and ajax

Question

I\'m trying to create a page with two functional parts:

• a form which the user fills and submits many times
• a chart which updates every time the user submi

Answer 1

Why not return JSON with validation errors when form contains invalid data? Django has a Form.errors fields which contains validation errors for each field. These field can easily be converted to JSON and used to mark your inputs invalid:

Your view:

def submit_form_view(request):

    if request.method == 'POST': # If the form has been submitted...
        form = ChartForm(request.POST) 
        if form.is_valid():    # All validation rules pass
            # Return JSON response if form was OK
            response_data = {'form_saved':True, 'data':'somedata'}    
            return HttpResponse(json.dumps(response_data), mimetype="application/json")
        else:                     # Invalid data:
            # Send what were errors
            response_data = {'form_saved': False, 'errors': form.errors}
            return HttpResponse(json.dumps(response_data), mimetype="application/json")

    else:
        form = ChartForm() # An unbound form

    return render_to_response('contact.html', {
        'form': form,
    })

Javascript code:

$.ajax({
  url: '{% url someapp.submit_form_view %}',
  success: function(data) {
      if( data.form_saved ){

            $('#form input').removeClass('error'); // Form submit ok -> remove error class of all fields

            var chart_data = data.chart_data;
            // Update the chart here   

      }else{
            var form_errors = data.form_errors;

            // Display form validation errors
            for(var fieldname in form_errors) {

                var errors = form_errors[fieldname];       // Array of error strings for fieldname

                $('#form input[name="'+fieldname+']').addClass('error')

            }
      }      
  }
});