observe_field and datetime_select

Hello all,

I have a form with a datetime_select.
I need to use the actual time selected in an action triggered by observe_field.

Could make it work with other select fields, but not with datetime_select.

Seems that observe_field can locate the element just by the id (not by the name).
If so, how can I set the ID of datetime_select ???

I’m in this for some hours, but could not find a solution…

Thanks for any help…