jQuery-Ajax-JSON-简单联系表单不起作用

我正在努力适应这种提交表单的方法。我正在尝试使用JSON并了解这里发生了什么。。。但我觉得我错过了一些非常明显的东西。。。我真的很想让它发挥作用。非常感谢。

这是HTML

<div class="span4">
        <div id="formResponse"></div>
        <form id="contactForm" name="contactForm" method="post">
        <div class="controls">
            <input class="span4" type="text" name="name" id="name" placeholder="Name" required />
        </div>
        <div class="controls">
            <input class="span4" type="email" name="email" id="email" placeholder="E-mail" required />
        </div>
        <div class="controls">
            <textarea rows="3" class="span4" name="message" id="message"placeholder="Leave your message at the beep..."></textarea>
        </div>
        <div class="controls">
            <input type="submit" class="btn btn-primary" name="formSubmit" id="formSubmit" value="Send E-Mail" />
        </form>
        </div>          
        </div>

这是jQuery:

    <script type="text/javascript">
$(document).ready(function(){
    $('#contactForm').submit(function(){
        $.ajax({
            type: "POST",
            url: "php/contact.php",
            data: $("#contactForm").serialize(),
            dataType: "json",
                success: function(msg){
                $("#formResponse").removeClass('error');
                $("#formResponse").removeClass('success');
                $("#formResponse").addClass(msg.status);
                $("#formResponse").html(msg.message);
            },
            error: function(){
                $("#formResponse").removeClass('success');
                $("#formResponse").addClass('error');
                $("#formResponse").html("There was an error submitting the form. Please try again.");
            }
        });
    });
});
</script>

这是PHP:

function checkEmail($email){
if(eregi("^[a-zA-Z0-9_]+@[a-zA-Z0-9'-]+'.[a-zA-Z0-9'-'.]+$]", $email)){
    return FALSE;
}
list($Username, $Domain) = split("@",$email);
if(@getmxrr($Domain, $MXHost)){
    return TRUE;
} else {
    if(@fsockopen($Domain, 25, $errno, $errstr, 30)){
        return TRUE;
    } else {
        return FALSE;
    }
}
}   
$response_array = array();
if(empty($_POST['name'])){
//set the response
$response_array['status'] = 'error';
$response_array['message'] = 'Name is blank';
} elseif(!checkEmail($_POST['email'])) {
//set the response
$response_array['status'] = 'error';
$response_array['message'] = 'Email is blank or invalid';
} elseif(empty($_POST['message'])) {
$response_array['status'] = 'error';
$response_array['message'] = 'Message is blank';
} else {
//send the email
$body = $_POST['name'] . " sent you a message'n";
$body .= "Details:'n'n" . $_POST['message'];
mail($_POST['email'], "SUBJECT LINE", $body);
//set the response
$response_array['status'] = 'success';
$response_array['message'] = 'Email sent!';
}
echo json_encode($response_array);