I highly recommend jQuery. There are several tutorials on how to implement it.
http://lethain.com/entry/2007/dec/11/two-faced-django-part-5-jquery-ajax/
http://lethain.com/entry/2007/dec/01/using-jquery-django-autocomplete-fields/
http://vincentxu.net/minimal-ajax-in-django-with-jquery-post
NOTE: Microsoft also announced a while ago that jQuery would be the official client-side framework for ASP.NET MVC, so its good to know regardless of what server side framework you’re using.