python - Implementing dynamic dropdown menu in django -

i want create dynamic drop-down menu car details

so created 4 models models.py

class companymake(models.model):     company_name = models.charfield(max_length = 100)     def __unicode__(self):         return self.company_name  class makemodel(models.model):     company = models.foreignkey(companymake)     model_name = models.charfield(max_length = 100)     def __unicode__(self):         return self.model_name  class modelparts(models.model):     company = models.foreignkey(companymake)     model = models.foreignkey(makemodel)     part_name = models.charfield(max_length = 100)     def __unicode__(self):         return self.part_name  class modelyear(models.model):     company = models.foreignkey(companymake)     model = models.foreignkey(makemodel)     year_value = models.integerfield()   class userprofile(models.model):     user = models.onetoonefield(user,primary_key=true)        #image = models.imagefield(upload_to=get_photo_storage_path, null = true, blank=true)     part = models.foreignkey(modelparts,null = true, blank=true)      phone_number = models.charfield( max_length = 10,verbose_name="mobile number 10 digits",null = true, blank=true, default=none) 

now want create drop-down menu car, model, part , year if particular car selected models related car should in next model drop-down, if particular drop-down selected parts related model should in next part drop-down menu same year.

my views.py

def home(request):     cm = companymake.objects.all()     in cm:         print         mm = a.makemodel_set.all()         b in mm:             print b             mp = b.modelparts_set.all()             c in mp:                 print c                 = modelyear.objects.all()                 print          return render(request,'choice.html',{'cm':cm,'mm':mm, 'mp':mp, 'my':my}) 

my choice.html file is

<select name="car">     {% car in cm %}              <option value="{{car.key}}" selected="selected">{{car.company_name}}</option>      {% endfor %} </select>          <br/> 

please guide me in right direction. getting car models drop-down menu. in above way can drop-down menu not related each other. want drop-down menu in related order. car related models should there, models related parts should there.