Newbie: Using text_field for date and select_time for time


I am having java script to enter the date using a calander to a
text_field and having separate select_time for the time selection.

but we want the controller end to have the normal ruby time format by
concatenating the entered time using select_time and entered date using
the text_field (via the calendar)

Could someone please let me know how I could do it? I am not sure
whether I explained my self well but if you have any questions please
let me know