Google recaptcha onepage issue - recaptcha

Question

I've an HTML onepage website.
I want insert google recaptcha 2.0 system but something go wrong with js.
When i click on submit button no success message is shown and no message is sent.
The button Send remains clicked and no further actions happen.
WIth the original php file on bottom the form works. But i've to insert recaptcha, too much spam.
Could someone help?
Thank you
Scipio
HTML CODE
<script src="https://www.google.com/recaptcha/api.js" async defer></script>
<form name="frmcontact" action="php/send.php" class="contact-frm" method="post">
<input type="text" required placeholder="Nome" name="txtname">
<p class="twocolumn">
<input type="email" required placeholder="Email" name="txtemail">
<input type="tel" placeholder="Phone" name="txtphone">
</p>
<div class="g-recaptcha" data-sitekey="xxx"></div>
<textarea placeholder="Testo del Messaggio" name="txtmessage"></textarea>
<input type="submit" class="button" value="SEND" name="btnsend">
PHP CODE THAT I WANT TO INSERT:
<?php
if(isset($_POST['btnsend']) && !empty($_POST['btnsend'])):
if(isset($_POST['g-recaptcha-response']) && !empty($_POST['g-recaptcha- response'])):
//your site secret key
$secret = 'XXX';
//get verify response data
$verifyResponse = file_get_contents('https://www.google.com/recaptcha/api/siteverify?secret='.$secret.'&response='.$_POST['g-recaptcha-response']);
$responseData = json_decode($verifyResponse);
if($responseData->success):
//contact form submission code
$name = !empty($_POST['txtname'])?$_POST['txtname']:'';
$email = !empty($_POST['txtemail'])?$_POST['txtemail']:'';
$email = !empty($_POST['txtphone'])?$_POST['txtphone']:'';
$message = !empty($_POST['txtmessage'])?$_POST['txtmessage']:'';
$to = 'XXX';
$subject = 'New contact form have been submitted';
$htmlContent = "
<h1>Contact request details</h1>
<p><b>Name: </b>".$name."</p>
<p><b>Email: </b>".$email."</p>
<p><b>Phone: </b>".$phone."</p>
<p><b>Message: </b>".$message."</p>
";
// Always set content-type when sending HTML email
$headers = "MIME-Version: 1.0" . "\r\n";
$headers .= "Content-type:text/html;charset=UTF-8" . "\r\n";
// More headers
$headers .= 'From:'.$name.' <'.$email.'>' . "\r\n";
//send email
#mail($to,$subject,$htmlContent,$headers);
$succMsg = 'Your contact request have submitted successfully.';
else:
$errMsg = 'Robot verification failed, please try again.';
endif;
else:
$errMsg = 'Please click on the reCAPTCHA box.';
endif;
else:
$errMsg = '';
$succMsg = '';
endif;
?>
JS CODE:
$('form[name="frmcontact"]').submit(function () {
var This = $(this);
if($(This).valid()) {
var action = $(This).attr('action');
var data_value = unescape($(This).serialize());
$.ajax({
type: "POST",
url:action,
data: data_value,
error: function (xhr, status, error) {
confirm('The page save failed.');
},
success: function (response) {
$('#ajax_contact_msg').html(response);
$('#ajax_contact_msg').slideDown('slow');
if (response.match('success') != null) $(This).slideUp('slow');
}
});
}
return false;
});
ORIGINAL PHP CODE:
<?php
if(!$_POST) exit;
$to = 'gopal#iamdesigning.com'; #Replace your email id...
$name = $_POST['txtname'];
$email = $_POST['txtemail'];
$phone = $_POST['txtphone'];
$subject = 'Support';
$comment = $_POST['txtmessage'];
if(get_magic_quotes_gpc()) { $comment = stripslashes($comment); }
$e_subject = 'You\'ve been contacted by ' . $name . '.';
$msg = "You have been contacted by $name with regards to $subject.\r\n\n";
$msg .= "$comment\r\n\n";
$msg .= "You can contact $name via email, $email.\r\n\n";
$msg .= "-------------------------------------------------------------------------------------------\r\n";
if(#mail($to, $e_subject, $msg, "From: $email\r\nReturn-Path: $email\r\n"))
{
echo "<span class='success-msg'>Thanks for Contacting Us, We will call back to you soon.</span>";
}
else
{
echo "<span class='error-msg'>Sorry your message not sent, Try again Later.</span>";
}
?>