Special Edition Using® Microsoft® ASP.NET

Introduction to Data Validation in ASP.NET

There are two types of data validation: client-side data validation and server-side validation. They are both valuable techniques, and they both have their place.

Client-side validation happens inside the browser. Before a form is submitted back to the server, a piece of client-side script looks at the data and decides whether it is valid. Right now (before the official release of ASP.NET) the developer writes the script, which must evaluate the data to ensure it is correctly evaluated. For years, developers have done this as they create robust Web applications. Unfortunately, though, they end up writing the same code over and over again, which is a very inefficient way to go about developing Web applications. ...