[Javascript] Form validation wrong=no upload

[Jamesjackson73 at aol.com]

Just on the final stages of a form that uploads a file and emails the contents of the form fields, The only Validation I can find still uploads the file even though it did find wrong/blank entries. I want it to return to the form without emailing and uploading.
Can anyone point me to script that does that...
Thanks in advance
James