script no enum forcing input of specified values for a drop down

So I am writing a function in javascript that will be consumed by keyword tests and other script tests. It adds a record to a database through the user interface form. On the form there are some drop down lists with fixed lists of values. I want to force the caller of the function to use one of the predefined values, present with a list or whatever.

Given this is scripting, I don't think I can do that. Maybe all I can do is handle invalid values in the function. But TestComplete is sometimes more clever than the scripting language it uses. Does anyone know TestComplete Magic that could support this?

Thanks