Practically every website contains web forms, whether it's a simple feedback form or a new user registration process. To ensure that the data sent by the user is correctly received and processed, it's necessary to check that the web form is filled out correctly. This is done through validation. Valid data can be sent to the server and stored in the database. In case the user has made a mistake when filling out the form (intentionally or not), the data should not be saved to the database.
According to the international standard ISO 9000, validation is a confirmation that the requirements set out for a specific use have been met. Validation should answer the question «Are we making the right product?».
There are two types of form validation from a technical point of view:
- client-side validation;
- server-side validation.