Having Problems with Form Validation...

I keep looking at it, and everything looks all right to me...
I think either there's something vital that I'm missing that I just can't spot on my own, or that I've just messed up in a way that I can't solve on my own.

Can anyone help me out?

http://web.niaccist.niacc.edu/~christophersonmp/webdev2/final/circus.html

Could you be more specific?

You mean in what it's supposed to do?

It's supposed to send error messages if a required field isn't filled out, and it's supposed to e-mail the results to me--although I think that's part of the PHP I haven't gotten to yet.

Here's the basics I was given:
#

Use JavaScript to ensure that data is legitimate, for example, the number of clowns in the little car can only be an integer.
# Use PHP to create an XML document holding the data

Convert the form data to XML and write it to a file using PHP. Store the file on the server.