php ajax联系表格

Im building a contact form using php and ajax with following code:

HTML:

<head>
<script src="js/app.js"></script>      
</head>
<body>
<form id="ajax-contact" method="post" action="php/mailer.php">    
   <input type="text" id="name" name="name" required>
   <input type="text" id="email" name="email" required>
   <textarea id="message" name="message" required></textarea>    
   <input class="submit" type="submit" value="Send">
</form>
<div id="form-messages">
</div>
</body>

AJAX:

$(function() {
    var form = $('#ajax-contact');

    var formMessages = $('#form-messages');

});
$(form).submit(function(event) {
    event.preventDefault();

});
var formData = $(form).serialize();

$.ajax({
    type: 'POST',
    url: $(form).attr('action'),
    data: formData
}).done(function(response) {
    $(formMessages).removeClass('error');
    $(formMessages).addClass('success');

    $(formMessages).text(response);

    $('#name').val('');
    $('#email').val('');
    $('#message').val('');
}).fail(function(data) {
    $(formMessages).removeClass('success');
    $(formMessages).addClass('error');

    if (data.responseText !== '') {
        $(formMessages).text(data.responseText);
    } else {
        $(formMessages).text('Oops! An error occured and your message could not be sent.');
    }
});

MAILER:

<?php

    if ($_SERVER["REQUEST_METHOD"] == "POST") {
        $name = strip_tags(trim($_POST["name"]));
                $name = str_replace(array("","
"),array(" "," "),$name);
        $email = filter_var(trim($_POST["email"]), FILTER_SANITIZE_EMAIL);
        $message = trim($_POST["message"]);

        if ( empty($name) OR empty($message) OR !filter_var($email, FILTER_VALIDATE_EMAIL)) {
            http_response_code(400);
            echo "Oops! There was a problem with your submission. Please complete the form and try again.";
            exit;
        }

        $recipient = "mailreceiver@example.com";

        $subject = "New contact from $name";

        $email_content = "Name: $name
";
        $email_content .= "Email: $email

";
        $email_content .= "Message:
$message
";

        $email_headers = "From: $name <$email>";

        if (mail($recipient, $subject, $email_content, $email_headers)) {
            http_response_code(200);
            echo "Thank You! Your message has been sent.";
        } else {
            http_response_code(500);
            echo "Oops! Something went wrong and we couldn't send your message.";
        }

    } else {
        http_response_code(403);
        echo "There was a problem with your submission, please try again.";
    }

?>

In Ajax on action I load the php mailer file to send the mail to my current mail address BUT I want to do this in the background the page shouldn't be loaded since I'm using ajax... I want to stay on the html page of the form without redirecting to that php page for sending that mail and just display succes or failure in the div:form-messages.

What am I missing here?

try with this:

Bind your input submit button with class "submit" to submit the form using ajax. And you can reset the form using $(form)[0].reset(); insead of clear input values

$('.submit').click(function() { //<-- changed/new
    var form = $('#ajax-contact');
    var formMessages = $('#form-messages');
    var formData = $(form).serialize();

    $.ajax({
            type: 'POST',
            url: $(form).attr('action'),
            data: formData
    }).done(function(response) {
            $(formMessages).removeClass('error');
            $(formMessages).addClass('success');

            $(formMessages).text(response);

            $(form)[0].reset(); //<-- changed/new

    }).fail(function(data) {
            $(formMessages).removeClass('success');
            $(formMessages).addClass('error');

            if (data.responseText !== '') {
                $(formMessages).text(data.responseText);
            } else {
                $(formMessages).text('Oops! An error occured and your message could not be sent.');
            }
    });
});

try with something like this:

$('.submit').click(function(event) {
    //use this to dont submit the form
    event.preventDefault(); 
    //your ajax stuff
    $.ajax....
    //if you dont want to use the preventDefault function just
    return false;
}

Try removing action="php/mailer" and do something like the following

function sendEmail(message){
    var data = new XMLHttpRequest();
    data.open("POST","php/mailer.php");

    data.onreadystatechange = function(){
        if(data.readyState === 4 && data.status === 200){
            document.getElementById('results').innerHTML = "Email sent";
        }
    }
    data.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
    data.send("message=" + message);
}

the you can call the function in the submit button.