Web Design Garage

Chapter 70. Validating Form Input

Even though you need server-side coding to process form data, you can use good old client-side scripting to review the visitor's submission before it goes to the Web server. This process is called validation, and it's a very good idea for most types of forms.

A validation pass helps to prevent errors, both intentional and accidental, from confusing or crashing the server-side code that eventually receives the form data. Say your form asks visitors to supply an email address so that the server-side form handler can send out a confirmation email. Obviously, you need the visitor to supply an email address, or the server-side code won't work right. If someone out there gets clever and tries to leave the field blank ...