CFSelect Change required attribute based on user input

I would like to upload text to a db and give users the option to upload associated files on the same form. If they choose to upload a file by using the cffile tag file selector (file1), I need to require them to select a file type from a cfselect tag (type1) to route the file to its proper desitination of the server. The problem is that if I make the type1 field required, I can't submit the form without selecting a type even though their is no file to upload. If type1 isn't required, the file won't be uploaded to the proper directory.

My thought is to make the type1 field required only if a file is selected by the user using the onchange attribute. How can I do this? or is their a better way still using client-side validation?

Thanks for your help.