Microsoft Expression Web 4 in Depth

29. Form Validation Using ASP.NET

The Need for Form Validation

You’re no doubt familiar with the saying “Garbage in, garbage out.” Web applications that require data entry by users provide the perfect opportunity to put that old saying into practice. Try as you might, you can never predict the actions of users of your site. That’s why you must take every opportunity to prevent any user from shooting himself or herself in the foot, or worse yet, corrupting your data with bad input.

Web developers have always struggled with implementing robust form validation. Many web developers are not experts at client-side scripting, and because the most efficient form validation is client-based, that puts them at a distinct disadvantage. Perhaps you are ...