title: Zend form dynamically update options
body: <p>I am using zend framework and want to create a zend form where the user selects (using dropdowns) a country. Depending on the country, I would like the second 'region' dropdown to populate with the appropriate regions. Again, depending on the selected region, I would like a dropdown of cities to be populated. In each case, until the preceding values has been selected, I would like the next dropdown to be empty.
  I am using doctrine2 and want these to be populated from the db.</p>
  
  <p>What would be the best way to achieve this?</p>