Only one message now appears when you sign-up and don't put both names. Note however, that if the first name is the one missing, it will still render across two lines with the error message
Removed use of id when selecting textbox, and shortened function expression to make it more concise
Added myself as a contributor

Fixed minor indentation issue

Fixed error message
Merge pull request #138 from JGulbronson/master

Only one message now appears when you sign-up and don't put both names.