How to bind a Javascript function / AJAX call to display an alert

[Ben Synes]

Hi

I have an EditUser.jsp which has a form, with multiple users, the id for each is submitted to a DeleteServlet via the form action "deleteUser". A request forward after the delete redirects the user back the list of users, the functionality all works.

However, there can be a case where the logged in user can attempt to delete themselves, Ive blocked this on the back end, but I would like to render a popup on the front end to say this.

I managed to hook up a AJAX call, but this would not open the popup, and would display the message on the page transition I mentioned above, from the form action.

Some snippets below:
main.js

function doDelete(userId){
    $.ajax({
        cache: false,
        type: "POST",
        url: "/admin/deleteUser",
        data: "userId=" + userId,
        success: function(result){
            alert(result);
            location.reload();
        }
    });
}

DeleteUserServlet.java

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String userId = req.getParameter("userId");
        HttpSession session = req.getSession();
        String id = (String)session.getAttribute("id");

        if(isLoggedInUser(id, userId)) {
            System.out.println("not deleted");
            PrintWriter out = resp.getWriter("false");
        } else {
            deleteUser(userId); // removes from the db
            RequestDispatcher dispatcher = req.getRequestDispatcher("/user_pages/showUsers.jsp");
            dispatcher.forward(req, resp);
        }
    }

showUsers.jsp (just a snippet of the form)

<form action="deleteUser" method="post">
<input type="submit" value="Delete" onclick="doDelete(1); return false;  /></form>

The for I hoped for was, hit delete -> check the user -> if loggedin user -> show popup -> user dismisses popup

ARE THERE ANY BETTER SOLUTIONS! I know nothing about JS, or JQuery, this small project is to try and learn so...
Any help appreciated.

My source for trying to implement this is from: webpage

The strange thing is, when I use the chrome dev tools and type the function name in the console, it works, just when running the app, it wont open the

[Paul Clapham]

If I understand that correctly (and I think I do, it's a pretty clear set of example code) then the client doesn't know the current user ID. It's kept in the session on the server, but I don't see it being sent to the client. If that's the case then it wouldn't be possible for the Javascript code to check whether the user is trying to delete themselves.

But what you've got seems like a reasonable start. You just need to fix the servlet to forward to the showUsers JSP in all cases, and if the user tried to delete themselves then set a request attribute which will cause that JSP to include a message saying so.