Soy novato en django. Estoy usando ajax simple para actualizar dinámicamente el campo de elecciónsemestre sobre la base decurso selección. Pero al enviar el formulario recibo el errorSelecciona una opción válida.opción seleccionada No es una de las opciones disponibles. El código es el siguiente:

formas.py:

from django import forms
from feedback_form.models import course,section_info

class loginForm(forms.Form):
     iquery1 = course.objects.values_list('course_name', flat = True)
     iquery1_choices = [('', '----------')] + [(id, id) for id in iquery1]
     sem_choices = [('', '----------')]

     course_name = forms.ChoiceField(iquery1_choices,required=True, widget=forms.Select())
     semester = forms.ChoiceField(sem_choices, required= True, widget=forms.Select())

views.py:

def get_batch(request, c_id):
    current_course = feedback_form.models.course.objects.get(course_name=c_id)
    batches = feedback_form.models.batch.objects.all().filter(course_id=current_course)
    no_of_sem = feedback_form.models.course.objects.values_list('number_of_sem', flat=True).filter(course_id = current_course)
    no_of_sem = int(no_of_sem[0])
    batch_dict = {}
    for batch in batches:
         batch_dict[batch.batch_id] = batch.batch_id
    sem = {}
         sem[no_of_sem] = no_of_sem
    data = [batch_dict, no_of_sem]
    return HttpResponse(json.dumps(data))

loginForm.html:

 <form action="" method="post">
    <table>
        {{ form.as_table }}
    </table>
    {% csrf_token%}
    <input type="submit" value="Submit">
 </form>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script>

$(document).ready(function(){
$('#id_course_name').change(function() {
    request_url = 'login/get_batch/' + c_id + '/';
    $.ajax({
        url: request_url,
        success: function(data){
            data = $.parseJSON(data);
            $('#id_semester').html('<option selected="' + "selected" + '">' + '' +'</option>');
            for(var i = 1; i<=data[1]; i++) //data[1] contains no of sem
                $('#id_semester').append('<option value="' + i + '">' + i +'</option>');
        }, 
        errors: function(e) {
            alert(e);
        }
    })

})

Por favor, ayúdame.