JavaScript works in debug mode but not working normal mode

Question

$(document).ready(function() {
    urlHolder.checkUser = '${checkUser}';
    $('#checkUserForm').submit(function() {
        checkUser();
    });
});

var urlHolder = new Object();
function checkUser() {
        $.post(urlHolder.checkUser, {
            email : $('#email').val(),
            password : $('#password').val(),
        }, function(response) {
            if (response != null) {
                alert('Success! User has been added.');
            } else {
                alert('Failure! An error has occurred!');
            }
        });
    };

I'm using this code for checking user exist or not. When I used firefox debugger (breakpoint on alert() line ), it worked and server came back a response, but if I didn't put any breakpoint, alert doesn't work, but server came back a response. Note: not only alert() but also window.location.href = " http://stackoverflow.com "; didn't work.

Answer 1

Change the following lines to prevent the form from being submitted:

$('#checkUserForm').submit(function(event) {
  event.preventDefault();
  checkUser();
});