As you all know, validating on the client-side only can be easily hijacked by disabling javascript. For this type of validation I am using the jquery validator plugin http://docs.jquery.com/Plugins/Validation. When all client-side validations are successful, and the form is submitted to the server, I reapeat the same validations on the server. But does any one of you know how I can invoke the client-side validator of the client to show errors that have been detected on the server?
Validating on the client side shows me nice error messages beneath each input field and an error summary at the top. But let's say I want to validate the username field upon registration. On the client I check whether the field has been left empty or if it follows the correct format but I cannot check if the username already exists. I can only check for such occurrence when the data arrives at the server. How can I show the same error layout after the submission takes place? Thanks for your ideas.
