/********************* WEB INTERFACE *********************/
<div id="dialog_login" title="Login">
                    <form style="height: 100px;">
                        <div>
                            Username
                        </div>
                        <div>
                            <input type="text" name="diabox_username" class="text ui-widget-content ui-corner-all" />
                        </div>
                        <div style="padding-top: 5px;">
                            Password
                        </div>
                        <div>
                            <span><input type="password" name="diabox_password" value="" class="text ui-widget-content ui-corner-all" /></span>
                        </div>
                        <div id="diabox_information">sdf</div>
                    </form>
                </div>

/************* JQUERY *****************/
<script type="text/javascript">
            $(function(){
                $( "#dialog_login" ).dialog({
                    autoOpen: false,
                    height: 253,
                    width: 250,
                    resizable: true,
                    draggable: false,
                    modal: true,
                    buttons: {
                        "Login": function() {
                            $data = "do=validateLogin";
                            $data += "&username=" + $("#dialog_login input:[name=diabox_username]").val();
                            $data += "&password=" + $("#dialog_login input:[name=diabox_password]").val();

                            $.ajax({
                                url: "/inc/user.bridge.php",
                                type: "POST",
                                data: $data,
                                success: function(msg){
                                    alert(msg);
                                    //$("#diabox_information").html(msg);
                                }
                            });
                        }
                    }
                });

                // Dialog Link
                $('#bt_login').click(function(){
                    $('#dialog_login').dialog('open');
                    return false;
                });
            });

        </script>
/*********** BRIDGE ****************/
if ($_POST['do'] == "validateLogin")
    {
        echo "test";
        /*$db_connection->connect();

        $username = $_POST['username'];
        $password = $_POST['password'];

        $usertype = $user->checkLogin($username, $password);

        echo $usertype;

        switch($usertype)
        {
            case 1: //Tipe user 'EXPERT

                    break;
            case 2: //Tipe user 'ADMIN'
                    break;
            case 3: //Tipe user 'CUSTOMER'
                    echo "<script>window.location.href='/user/index.php'</script>";
                    break;
            default: echo "wrong username or password";
        }

        $db_connection->disconnect();
        */
    }

/********************* PHP CLASS *********************/
function checkLogin ($username, $password)
    {
        $this->query = "SELECT  user_type
                        FROM    user
                        WHERE   username = $username
                        AND     password = $password;";
        $this->result = mysql_query ($this->query);
        $result = mysql_result($this->result, 0, 'user_type');


        if ($this->result)      //Username tersebut ada
            return $result;
        else                    //Username tersebut ga ada
            return 0;
    }