Question

I had web site I launched it on server and it worked well internal but when it being online this error appear in registration form

<error>

Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/> in configuration or <%@ Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation.

Answer 1

That error is being displayed because you’ve entered something in the form that isn’t deemed as safe by the validator. This is used in order to stop injection attacks, such as typing malicious javascript in the form.

If you type in the same things locally and “online” and still get that error, check to see if you have it turned off locally and turned on in your production environment.

It is recommended however to have enableEventValidation=”true” since it gives you a lot of security for free.