使用ajax验证重新计算的错误

am trying to validate recaptcha with ajax, the only problem am facing is that it always sais that recapthca was typed wrong!even when i did it right! i really wonder what is wrong with my code!

<?php
    require_once('recaptcha/recaptchalib.php');
    define("PUBLICKEY"," ");
    define("PRIVATEKEY"," ");

    $resp = recaptcha_check_answer ($privatekey, $_SERVER["REMOTE_ADDR"], $_POST["recaptcha_challenge_field"], $_POST["recaptcha_response_field"]);
    if ($resp->is_valid) {
    ?>success<?
        $name = $_POST['name'];
        $email = $_POST['email'];
        $phone = $_POST['phone'];
        $reason = $_POST['reason'];
        $header = 'From: ' . $email . " 
";
        $msg = "Sent from: " . $name . "
";
        $msg .= "Email: " . $email . " 
";
        $msg .= "Phone: " . $phone . " 
";
        $msg .= "Contact reason:" . $reason . " 
";
        $msg .= "Message: " . $_POST['message'] . " 
";
        $msg .= "Date and time " . date('d/m/Y', time());

        $to = '';
        $subject = 'contact page';

        mail($to, $subject, utf8_decode($msg), $header);
    }
    else 
    {
    die ("The reCAPTCHA wasn't entered correctly. Go back and try it again." .
       "(reCAPTCHA said: " . $resp->error . ")");
    }
?>

on the form page i have this

<?php 
    require_once('recaptcha/recaptchalib.php');
    define("PUBLICKEY","");
    define("PRIVATEKEY"," ");
?>

<div id="contact-form">
<?php echo  $content; ?>
        <form action="#" method="POST" id="contactForm" onSubmit="return validateCaptcha()">
    <div class="form">
            <label for="name">Your Name: <span class="requireds">(Required)</span><br /></label>
            <input id="name" name="name" class="text-input" minlength="2" />
   </div>
   <div class="form">
            <label for="email">Your Email:<span class="requireds">(Required)</span><br /></label>
            <input id="email" name="email" class=" text-input" />
   </div>
   <div class="form">
            <label for="phone">Your Phone:<br /></label>
            <input id="phone" name="phone" type="text"  maxlength="200" class="text-input"  />
   </div>
   <div class="form">
            <label  for="reason">Contact reason:<br /></label>
            <select id="reason" name="reason" class="select">
                <option>Sales question </option>
                <option>Time/ Delivery</option>
                <option>My existing Order</option>
                <option>Technical Question</option>
                <option>Revision/ Support</option>
                <option>Other</option>

            </select>
   </div>
   <div class="form">
            <label for="message">Message: <span class="requireds">(Required)</span> <br /></label>
             <textarea id="message" name="message" class="textarea"></textarea>
   </div>

   <div style="margin:10px 0; width:495px;  -moz-border-radius:3px; border-radius:3px;">
                <p style="color: #f14444; text-align:right; font-size:12px" id="captchaStatus">&nbsp;</p>
                    <?php echo recaptcha_get_html(PUBLICKEY); ?>

      </div>
       <input type="submit"  value="" class="send"/>

    </form> 

i already checked if the public and private key are correct.. does somebody have an idea about what is wrong on this code?

You are receiving this error when submitting the recaptcha which tells me that your API key is not being submitted properly:

To use reCAPTCHA you must get an API key from https://www.google.com/recaptcha/admin/create

Update:

recaptcha_check_answer ($privatekey,

See the problem there? You're using $privatekey instead of PRIVATEKEY so you're actually submitting nothing as your private key. The error was correct (trust the error messages!). I use Chrome's built in developer tools (Ctrl+Shift+i) to debug this.