sendEmail.php

<?php
    $to="";
    $sub="";
    $message="";
    $headers='From:'."\r\n".'Reply-To:'."\r\n".'X-Mailer:PHP/'.phpversion();
    $result=array();
    $result['success']=mail($to,$sub,$message,$headers);

    if(array_key_exists('callback', $_GET)){

        header('Content-Type: text/javascript; charset=utf8');
        header('Access-Control-Allow-Origin: http://www.example.com/');
        header('Access-Control-Max-Age: 3628800');
        header('Access-Control-Allow-Methods: GET, POST, PUT, DELETE');

        $callback = $_GET['callback'];
        echo $callback.'('.json_encode($result).');';

    }else{
        // normal JSON string
        header('Content-Type: application/json; charset=utf8');
        echo json_encode($result);
    }
?>