title: How to show related model fields when a foreign key is selected without submitting the form in django?
body: <p>Say you have two models:</p>
  
  <pre><code>class Author(models.Model):
      name = models.CharField(...)
      city = models.CharField(...)
      def __unicode__(self):
          return self.name
  class Article(models.Model):
      author = models.ForeignKey('Author', ...)
      text = models.TextField(...)
  </code></pre>
  
  <p>In django's admin interface, when creating (or editing) and Article, you get a drop down of the Authors listed by their name. When you select an Author (without pressing save), i want to see that Author's city as a readonly field. How would you go about doing this?</p>