For lookup list widgets, there is a built-in function that provides the record ID of the item selected in the list ?

For lookup list widgets, there is a built-in function that provides the record ID of the item selected in the list ?

Hi.
A lookup-picklist displays a list of names to choose from. I want to know the record ID# of the selected item.

Say, formA and formB.
In formB there is a lookup field that import data from formA.
After selection, i need to know the item's ID, cause i need to fetch from formA the value of the item (eg. ID 1, value "pippo", i need to fetch "pippo") and copy in a text field in formB.

i.ve tried with: var = formB [ID == lookupfield.ID], but it's wrong.

Please see this message: 
https://help.zoho.com/portal/en/community/topic/how-to-get-the-correct-record-id-from-a-selection-in-a-picklist-where-there-are-multiple-records-with-the-same-criteria%3f

Elia Spallanzani