remote function not submitting form

Hi all,

I have this code:

    <%= collection_select('declarations_payers', 'user', @users, 'id', 'fullname', {},         {:onChange => remote_function(           :update => "participants",           :url => { :controller => 'ajax',           :action => 'declaration_users' }           )         }     ) %>

It's inside a div, inside a form generated with form_tag.

But when I change the item of the selectlist, it doesn't submit the form data. Does anyone know what's the problem? Or maybe how I can solve this problem. I tried the serialize() function, but that can only be used for one field.

Thanks in advance!