How to get the current value of a select box?

Here is my code:

<%= observe_field 'search_form', :frequency => 0.5, :update => 'results', :url => { :controller => 'programs', :action=> 'get_results', :search_type => select_type }, # an error occurs :with => "'search_text=' + escape(value)"%> <%= select "select","type",{"BOY" => '1', "Girl" => '2'}%>

Can anyone tell me how to pass the value of the select box when i call
“get_results”?