NET controls on the page from rendering any non-HTML 3.2 compatible content.
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. Even if you need to perform a very specialized form validation task, you can do so by using this control.
Traditionally, Web developers have faced a tough choice when adding form validation logic to their pages.
Because server-side code functions correctly with any browser, this course of action was safer.
Fortunately, the Validation controls discussed in this chapter do not force you to make this difficult choice.
If a browser is incapable of supporting Java Script, the validation routines are automatically implemented in server-side code.