What are the best practices to keep in mind when accepting user input on a web application?
1. Always use validation controls whenever possible to limit user input to acceptable values. 2. Always check the IsValid property of the aspx page. Run the server side code only if the IsValid property value is true. A value of false means that one or more validation controls have failed a validation check. 3. Always perform server side validation irrespective of client side validation being performed or not. This will protect your web application even if the client has by passed the client side validation by disabling javascript in the web browser. 4. Also make sure to re validate user input in the business logic layer of your application.
