How to send mail from HTML popup

PHP Coding to send mail:

<?php
if(isset($_POST['m_email'])) {

// EDIT THE 2 LINES BELOW AS REQUIRED
$email_to = "xxxxxx@gmail.com";
$email_subject = "New Registration";

function died($error) {
// your error code can go here
echo "We are very sorry, but there were error(s) found with the form you submitted. ";
echo "These errors appear below.

";
echo $error."

";
echo "Please go back and fix these errors.

";
die();
}


// validation expected data exists
if(!isset($_POST['m_name']) ||
!isset($_POST['m_rname']) ||
!isset($_POST['m_email'])
!isset($_POST['m_phone'])
!isset($_POST['m_location'])
!isset($_POST['m_cuisine'])
) {
died('We are sorry, but there appears to be a problem with the form you submitted.');
}

$user_name = $_POST['m_name']; // required
$restaurant_name = $_POST['m_rname']; //required
$email_from = $_POST['m_email']; // required
$telephone = $_POST['m_phone']; // required
$location = $_POST['m_location']; // required
$cuisine = $_POST['m_cuisine']; // required

$error_message = "";
$email_exp = '/^[A-Za-z0-9._%-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';

if(!preg_match($email_exp,$email_from)) {
$error_message .= 'The Email Address you entered does not appear to be valid.
';
}

$string_exp = "/^[A-Za-z .'-]+$/";

if(!preg_match($string_exp,$user_name)) {
$error_message .= 'The Name you entered does not appear to be valid.
';
}


if(strlen($error_message) > 0) {
died($error_message);
}

$email_message = "Form details below.\n\n";


function clean_string($string) {
$bad = array("content-type","bcc:","to:","cc:","href");
return str_replace($bad,"",$string);
}



$email_message .= "User Name: ".clean_string($user_name)."\n";
$email_message .= "Restaurant Name: ".clean_string($restaurant_name)."\n";
$email_message .= "Email: ".clean_string($email_from)."\n";
$email_message .= "Contact No: ".clean_string($telephone)."\n";
$email_message .= "Location: ".clean_string($location)."\n";
$email_message .= "Cuisine: ".clean_string($cuisine)."\n";




// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
@mail($email_to, $email_subject, $email_message, $headers);

}
?>

And we have Java script to call the PHP cript from HTML page. Below is the script.


function regEmail(pg){
var request = $.ajax({
url: "./res_mail.php",
type: "POST",
data: {
action: "regEmail",
m_name:$("#m_name").val(),
m_rname:$("#m_rname").val(),
m_email:$("#m_email").val(),
m_phone:$("#m_phone").val(),
m_location:$("#m_location").val(),
m_cuisine:$("#m_cuisine").val()
},
//dataType: 'json'
dataType: 'html'
});

request.done(function (data) {
alert("Message Registered");
});
}


Using the above code its not triggering mail and its simply in the same page.
So can you any one help on this fix please