title: Django: Is it possible to build filtered drop down menus?
body: <p>I was wondering if it was possible to build two dropdown menus where the second has options dependent on what is selected in the first one? I have three classes, in the field 'step' in RouteStep is a series of processes, for example Heat Treatment and Removal. I'd like if one of these processes is selected, only fields from 'step_option' associated with that process shows up, similar to a dropdown where selecting a car manufacturer and only getting their models. Is this possible in django forms?</p>
  
  <pre><code>class Step(models.Model):
      name = models.CharField(_('Step Name'), max_length=100, default='')
      def __unicode__ (self):
              return self.name
  
  class StepOption(models.Model):
      step = models.ForeignKey(Step, related_name = 'Step', null = True)
      name = models.CharField(_('Step Option'), max_length=100, default='')
      def __unicode__ (self):
              return self.name + " - " + self.step.name
  
  class RouteStep(models.Model):
      step_number = models.PositiveIntegerField(_('Step Number'), default = 0)
      step =  models.ForeignKey(Step, related_name = 'Step+', null = True)    
      step_option = models.ForeignKey(StepOption, related_name = 'StepOption', null=True)
      def __unicode__ (self):
              return self.step_option
  </code></pre>