If the validation fails, the response is then sent back to the client, page that contains the web form is refreshed and a feedback is shown.This method is secure because it will work even if Java Script is turned off in the browser and it can’t be easily bypassed by malicious users. Ajax calls to the server can validate as you type and provide immediate feedback.
There's lots of good information on the Internet, but you will also find opinions, misconceptions, and inaccurate information. There are people who believe that we never walked on the moon and that the Holocaust never happened, so be careful when you read a web page. Look for what Wikipedia calls the "verifiability" of information.Read Wicked or Wonderful: Revisiting Wikipedia by Annette Lamb.In computer science, data validation is the process of ensuring that a program operates on clean, correct and useful data.It uses routines, often called "validation rules" "validation constraints" or "check routines", that check for correctness, meaningfulness, and security of data that are input to the system.Ideally, users will fill the web form with necessary information and finish their job successfully. In this article we will go beyond the validation itself and explore different validation and error feedback techniques, methods and approaches.
The goal of web form validation is to ensure that the user provided necessary and properly formatted information needed to successfully complete an operation.
Therefore, data validation should start with business process definition and set of business rules within this process.
Rules can be collected through the requirements capture exercise.
SSN, date, currency symbol) while semantic validation should enforce correctness of their values in the specific business context (e.g.
start date is before end date, price is within expected range).
The rules may be implemented through the automated facilities of a data dictionary, or by the inclusion of explicit application program validation logic.