This is a wonderful form script. It acts as a verifier for a basic mailto: form. It simply will not send until all the forms are filled out. But when a field isn't filled out, this posts a new page telling the user.
It takes a few different pages to make this work. I have offered it all to you in a Zip file below. Just get the file, open it, and put all the files inside in the same directory. Then run "index.html".