I'm working on a small database, that features a list of companies. What I have set up is 3 search fields, City, State and Zipcode.

What I'd like to do it on the HTML form make the user enter at least 2 fields. Either State & City, State & Zipcode, City & Zipcode.

Any Ideas on how I can do this?

Database is located here: http://www.alldata.com/pro/free/smartshops.htm

Thanks!