Spring mvc and Ajax

[Ram Zz]

Hello, I'm trying to learn how to use Ajax in Spring mvc reading tutorials on the web but none of them works for me.
My first application is a simple form with a username text field and a submit button. What I'm trying to do is display a <div> error message via Ajax if the username is wrong, or redirect to another jsp if the username is correct.

My code in the jsp is:

	$(document).ready(function() { 
            $('#form1').ajaxForm(function() { 
                alert("Data submmited!"); 
            }); 
        }); 

The code in the controller is:

	@ResponseBody
	@RequestMapping(value="/checkLogin.spring" , method = RequestMethod.POST)
	public ModelAndView compruebaLogin(HttpServletRequest request, HttpServletResponse response) throws Exception
	{
		String username = request.getParameter("username");
        if(username.equals("ramzx") return new ModelAndView("CustomersArea");    // <-- This does not work, it does not redirect
        else return /// ???? <-- I don't know how to modify a div in the first jsp
    }

Thanks in advance.