IN THIS CHAPTER
In this chapter, you learn how to use the Validation Web controls to validate the information that a user enters into an HTML form.
You can use the Validation controls to perform very different types of form validation tasks . For example, you can use the Validation controls to check whether a form field has a value, check whether the data in a form field falls in a certain range, or check whether a form field contains a valid e-mail address or phone number.
You can view "live" versions of many of the code samples in this chapter by visiting the Superexpert Web site at:
At the end of this chapter, you also learn how to create custom validation functions by using the CustomValidator control. Even if you need to perform a very specialized form validation task, you can do so by using this control.