Hi Elang, in MOI each object automatically gets a unique id value, you can get an object from its id by using the moi.geometryDatabase.findObject() function, like this:
var obj = moi.geometryDatabase.findObject( id );

But usually scripts don't do that, usually a script either generates an object using the GeometryFactory.calculate() function which returns an object list with the created objects in it, or works on selected objects which are returned by moi.geometryDatabase.getSelectedObjects() or by using an object picker.

It would be easier to show you in an actual script, what is it that you are trying to make your script do?

- Michael