Collecting user data is a basic function of many websites and web applications, from simple data collection techniques such as registration or login information, to more complex scenarios such as payment or billing information. It is important that only relevant and complete information is collected from the user. To ensure this, the web developer must enforce validation on all data input. It is also important to provide a good user experience while enforcing this data integrity. This can be done by providing useful feedback to the user regarding any validation errors their data may have caused. This chapter will show you how to create an attractive web form that enforces data integrity while keeping a high-quality user experience.

A very important point to note is that any JavaScript or jQuery validation is open to manipulation by the user. JavaScript and jQuery resides within the web browser, so a user with little knowledge can easily modify the code to bypass any client-side...