In ruby on rails there is a method called text_field_with_auto_complete. By default it will call a method on your controller with the name auto_complete_for_<form>_<field>. It will pass in a param value for the field you are updating. The details of this I am not going into here, they are well documented elsewhere.
For this exercise I am going to show how to setup the tag so that you can pass multiple field values.
Example:
<%= text_field_with_auto_complete :user,
:habitat_name,
{:class => 'input'},
{:with => "'&user[state]=' + jQuery('#user_state').val() +
'&user[habitat_name]=' + jQuery('#user_habitat_name').val()",
:skip_style => false} %>
In the example above I am using the jrails plugin to implement jQuery so the syntax is for jQuery. The key clause is the :with class. Here you will need to implement not only the primary field you want to pass, but can add any others you wish. In my case I have a user[:habitat_name] and user[:state]
