[Javascript] form validation function

[Cutter (JavaScript)]

I would like to write a form validation function where I pass the names 
of all of the fields to validate to the function, which then loops 
through the list to make sure that no field is empty and returns true.

There's a little more to it, but that's the basics. My question is, is 
there a way to test if a field is an input or a select? Since accessing 
select values (especially cross browser) is not so straight forward I 
will need to plan for this contingency. Any suggestions?

Cutter