Introduction to Forms
However, this page contains a more complete overview of how to write a basic form validation script.
On this page I give the code you need for checking user input in a form. Using these bits of code, you can write your own scripts to validate forms
I can’t give you a complete script, because each form and each check are different.
You’ll have to use the elements I explain on this page to build your own script. I created an example form and script that you can study to get the hang of it.