Hiding a drop-down field if field is empty

Hi ScriptExperts,

I am not able to hide a drop-down field, if the field has No value assigned to it.

This drop-down field is wrapped in a subform.

I have tried following scripts, but so far nuthing has clicked

1. if ( $.record.fieldname.data[*].field == "" ) then

$.presence = "hidden"

endif.

2. if ( $.record.fieldname.data[*].field == "null" ) then

$.presence = "hidden"

endif.

3. if ($.rawValue == "") then

$.presence = "hidden"

endif

I am applying these scripts both on the drop-down , as well as the subform enclosing it (hoping it will work somewhere! )

Can anyone please guide me where am i going wrong ? also..i have used these scripts in the Form ready , Layoue Ready events.

Many Thanks,

Aditi