<form id="registerForm" method="get" action="./RegisterUserController">
    <p>
        <label>Email</label>
        <input type="email"  id="email"><br/>
    </p>
    <p>
        <label>Password</label>
        <input type="password" id="password"><br/>
    </p>
    <p>
        <label>FirstName</label>
        <input type="text" id="firstName" ><br/>
    </p>
    <p>
        <label>LastName</label>
        <input type="text" id="lastName"><br/>
    </p>
    <p>
        <label>Address</label>
        <input type="text" id="address" ><br/>
    </p>


    <p>
        <label></label>
        <input type="submit" class="btn btn-primary" value="Register"/><br/>
    </p>    <br/>
</form>

$("form").submit(function(event) {
    event.preventDefault();

    var email = $("#email").val();
    var password = $("#password").val();
    var repeatPassword = $("#repeatPassword").val();
    var firstName = $("#firstName").val();
    var lastName = $("#lastName").val();
    var address = $("#address").val();

    //THIS PART JUST ADD SOME ERROR <div> ON PAGE
    if(email == "")
        showError("email","addedDivEmail","Email mora biti popunjen!");
    if(password == "")
        showError("password","addedDivPassword","Šifra mora biti popunjena!");
    if(repeatPassword == "" && password != "")
        showError("repeatPassword","addedDivRepeatPassword","Ponovite šifru!");
    if(firstName == "")
        showError("firstName","addedDivFirstName","Ime mora biti popunjeno!");
    if(lastName == "")
        showError("lastName","addedDivLastName","Prezime mora biti popunjeno!");
    if(address == "")
        showError("address","addedDivAddress","Adresa mora biti popunjena!");
    if(password != repeatPassword && password != "")
        showError("repeatPassword","addedDivRepeatPassword","Šifre se ne poklapaju!");

    if(!($("#addedDivEmail").length || $("#addedDivPassword").length || $("#addedDivRepeatPassword").length || $("#addedDivFirstName").length || $("#addedDivLastName").length || $("#addedDivAddress").length)){
        url = "./RegisterUserController";
        $.post(url,{ email: email}).done(function(data){
            if(data == false || data == "false"){
                showError("email","addedDivEmail","Email vec postoji u sistemu!");
            }
            else{

                $('#registerForm')[0].submit();
            }

        }).fail(function(){
            alert("failSubmit");
        });
    }

});

public class RegisterUserController extends HttpServlet {

@EJB
private IUserDaoLocal userDao;

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    String email = request.getParameter("email"); // NULL
    String password = request.getParameter("password");// NULL
    String firstName = request.getParameter("firstName");// NULL
    String lastName = request.getParameter("lastName");// NULL
    String address = request.getParameter("address");// NULL

    User newUser = new User(email,firstName,lastName,password,false,address);
    try{
        userDao.persist(newUser);
    }
    catch(Exception ex){

    }
    request.getSession().setAttribute("name", firstName + " " + lastName);
    request.getSession().setAttribute("email", email);

    response.sendRedirect(response.encodeRedirectURL("./user/registerNotification.jsp"));
    return;
}

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

    //ObjectMapper mapper = new ObjectMapper();
    //Gson gson = new Gson();
    //String message;
    System.out.println("DO POST");
    String email = request.getParameter("email");
    boolean isUnique = userDao.isEmailUnique(email);

    //message = gson.toJson(isUnique);
    PrintWriter out = response.getWriter();
    response.setContentType("application/json");
    out.write(Boolean.toString(isUnique));
    return;

}