<script type="text/javascript">
                $(document).ready(function () {

                    $("#submit_btn").on("click", function(){
                    var username = $("#username").val();
                    var pass = $("#password").val();

                    $.ajax({
                            type: "POST",
                            url: "https://www.magno.pt/areacliente/insert.php",
                            data: { username: username},
                            sucess: function () {
                            }
                           })
                    });
                });
            </script>