jquery ajax表单与securimage验证码

Question

我想放入securimage的验证码，但我的代码有问题。它没有读取检查验证码是否正确但仅保存数据并忽略验证码的条件。这是我的jquery代码，它允许我在我的数据库上保存数据而无需重新加载

(function() {

    if($('#contactform').length) {

        var $form = $('#contactform'),
        $loader = '<img src="images/preloader.gif" alt="Loading..." />';
        $form.append('<div class="hidden" id="contact_form_responce">');

        var $response = $('#contact_form_responce');
        $response.append('<p></p>');

        $form.submit(function(e){

            $response.find('p').html($loader);

            $.post("php/contact-send.php", $("#contactform").serialize(), function(response) {

                $response.find('img').remove();
                $response.find('p').removeClass().addClass('success type-2');
                $response.find('p').append('Your email has been sent!');
                $form.find('input:not(input[type="submit"], button), textarea, select').val('').attr( 'checked', false );
                $response.delay(1500).hide(400);



            });

            e.preventDefault();


        });             
    }
})();
/* end Contact Form */  

这是我的PHP代码处理我的数据

require_once "../includes/database.php";
session_start();
    include_once $_SERVER['DOCUMENT_ROOT'] . '/pcf/securimage/securimage.php';
    $securimage = new Securimage();
    if ($securimage->check($_POST['captcha_code']) == false) {  
        echo "<script language='javascript' type='text/javascript'>alert('Invalid Captcha!')</script>";
        echo "<script language='javascript' type='text/javascript'>window.open('contact.php?alink=c','_self')</script>";
        exit;
    }
    $cname=$_POST['name'];
    $cemail=$_POST['email'];
    $cmessage=$_POST['message'];
    $date=date("Y-m-d");    
            $sql = "INSERT INTO messages (sendername,senderemail,message,datesent) VALUES (:name,:email,:message,:date)";
            $qry = $db->prepare($sql);
            $qry->execute(array(':name'=>$cname,':email'=>$cemail,':message'=>$cmessage,':date'=>$date));