update partial after submit need Help

hi

here i have a todo manager. i'm render the whole todo with a partial.
after i submit a new todo how can i refresh the todo partial
samethin lik this

<div>
     <%=render :partial=>"todos" %>
</div>

<div>
      -- here my new todo submit form
</div>

after the new todo submit form submition i need to refresh the partial
todos