"observe_field" and "onblur"

I've a text_field_tag (dom-id: tag) in a form (http://
pastie.textmate.org/59525). Now I'd like it to have this kind ob
behaviour:

The user types in some stuff and as soon as he hits the tabulator-key
some fancy javascript/ajax stuff happens before the cursor jumps to
the next text_field_tag.

I assumed this would be done using an observe_field-method with the
value "blur" on the :on-parameter as seen here: http://pastie.textmate.org/59526

Well, nothing happens. No error, no debug information using firebug,
it just seems as if the browser would ignore that observe_field-stuff.

Does anyone have a clue?

I guess monday hasn't arrived to my brain yet. :slight_smile:

solution:
i did forget to add <%= observe_tag_textfield -%> in my view.