Get a Selected value

Hi,

I wonder how is possible to get a value that has been selected from the
elemenet “select” within a form.

This is my case:

<td><%= select :worker_contract, :contract_type_id,

contract_types_for_select.map{|c| [c.name, c.id]}, {:class =>
‘w150’, :selected => nil, :disabled => !admin?} %>

I would like to filter the value that the user selects on this dropdown

list.

Could you help me?

Best Regards