联系表格jquery php phonegap - 成功问题

Question

我尝试在jquery php 4 phonegap中创建一个联系表单，我的问题如何才能从php获得成功？或者如果我可以尝试其他解决方案，但目前没有想法4 ^^ 很多

P.S。表单有效（如果我删除响应成功表格js）

index.js

$(document).on('pageinit', function() {
$('#send').click(function() {
            var url = 'send02.php';
            var error = 0;
            var $contactpage = $(this).closest('.ui-page');
            var $contactform = $(this).closest('.contact-form02');
            $('.required', $contactform).each(function(i) {
                if($(this).val() === '') {
                    error++;
                }
            });
            // each
            if(error > 0) {
                alert('Inserisci tutti i campi obbligatori segnati con asterisco*.');
            } else {
                var email = $contactform.find('input[name="email"]').val(); 
                var datetime = $contactform.find('input[name="datetime"]').val();   
                var mobilephone = $contactform.find('input[name="mobilephone"]').val(); 
                var selectnative4 = $contactform.find('select[name="selectnative4"]').val();
                var message = $contactform.find('textarea[name="message"]').val();


                //submit the form
                $.ajax({
                    type : "POST",
                    url : url,
                    data : {
                        email : email,
                        datetime : datetime,
                        mobilephone : mobilephone,
                        selectnative4 : selectnative4,
                        message : message
                    },
            success : function(data) {
                        if(data == 'success') {
                            // show thank you
                            $contactpage.find('.contact-thankyou').show();
                            $contactpage.find('.contact-form').hide();
                        } else {
                            alert('Impossibile inviare il messaggio. Per piacere riprova.');
                        }
                    }
                });
                //$.ajax

            }
            return false;
        });


});

和send.php

<?php
header('content-type: application/json; charset=utf-8');

if (isset($_GET["email"])) {
$email = strip_tags($_GET['email']);
$datetime = strip_tags($_GET['datetime']);
$mobilephone = strip_tags($_GET['mobilephone']);
$selectnative4 = strip_tags($_GET['selectnative4']);
$message = strip_tags($_GET['message']);
$header = "From: ". $firstname . " <" . $email . ">rn"; 

$ip = $_SERVER['REMOTE_ADDR'];
$httpref = $_SERVER['HTTP_REFERER'];
$httpagent = $_SERVER['HTTP_USER_AGENT'];
$today = date("F j, Y, g:i a");    

$recipient = 'mark@facebook.com';
$subject = 'Prenotazione Online';
$mailbody = "

Nominativo: $email

Telefono: $mobilephone 

data prenotazione: $datetime

Scelta dal Menù: $selectnative4

Messaggio: $message 
in data: $today
";
$result = 'success';

if (mail($recipient, $subject, $mailbody, $header)) {
    echo json_encode($result);
}
}
?>