autocomplete after update

I am trying to just render an ajax request to display the values at a
site when the user selects a site, I have this:

<%= text_field_with_auto_complete :site, :name,
:with => "'ci=' + element.value ",
:after_update_element => remote_function( :url => { :controller =>
'sites', :action => 'updatesearch' } ) %>

It is not doing anything when I select a value. Any ideas?