Using passed-in locals in observe_field in a partial

Rails
1

I need to be able to assign a value to the field_id field of
observe_field inside a partial. Ideally, it would look something like:

<%= observe_field(local_variable_name1, :url => {:action =>
‘some_constant’, :id => local_variable_name2}) %>

I’m not having a problem with the assignment to :id of
local_variable_name2. But I can not figure out how to use a local in
the field_id field. Any ideas?

TIA,
Bill