By the by, testing for opName == "" is kind of pointless.
A user could enter a single space, just for example, and it won't == "".
If you are going to bother to make a test, make it a useful one.
There are tons of examples of useful form validation in this very forum. Do a quick search.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.