Validating in a web user control online dating service that
The first and most obvious information that should be validated is required information – information without which operation cannot be completed successfully.
Thus, validation has to ensure that the user provided all the necessary details in the web form and it has to fail if at least one of the fields is not provided.
Server-side validation is enough to have a successful and secure form validation.
Apart from ensuring that users provide necessary information, validation has to ensure that users provide information in the correct format.
A simple message that all fields are required is enough. According to that survey “designers tend to remove all unnecessary details and distractions which don’t help the user to complete the form”.
More detailed analysis showed a trend of using very few mandatory fields – more than 50% of forms used at most 5 mandatory fields, while optional fields were often avoided.
On the other hand, users will have to fill in the information without getting a response until they submit the form. Validation in this context refers to validating rules such as username availability.
You can read more about validation with Ajax in this excellent tutorial on j Query For Designers.