form validation in php [closed]

Answer 1

the method I like to use is this (this is in the context of an MVC application)

1. Form in a View is set to POST back to own URL.
2. When the controller receives a POST request, validation is performed. If errors aren't found, the relevant action is taken, and then a HTTP redirect is sent back to the browser to send them to correct "success" page.
3. If validation fails, the original form is displayed, and each field displays the entered data. Invalid fields show error messages.