It seems that there are no error handling facility in the Jquery.Form plugin, which is very frustrating. Even though the documentation says we can use the $.ajax options, I
Just found out that the jquery.form plugin itself doesn't handle server error, because it doesn't have access to response headers due to the way 'file input' tag handles file upload. So I think the W3C needs to review that troublesome tag that not only doesn't let you style it with CSS but also doesn't make server response handling easy.
There must be a way around it though...
Let me know if I said something wrong and let me know your thoughts about this 'file input' tag...