error on contact form submit via jquery ajax - php

Question

Based on this question i had to rewrite my contact form script.
The goal is to to have a send button labeled send. After clickick it should show sending till the php script is done. When its done it should show sent.
Thats my simple form:
<form id="contactForm" action="mail.php" method="post">
<input type="text" id="name" name="name" placeholder="Name" required><br />
<input type="text" id="email" name="email" placeholder="Mail" required><br />
<textarea name="message" id="message" placeholder="Nachricht" required></textarea><br />
<button name="submit" type="submit" id="submit">send</button>
</form>
Here is the jquery script for the label changing and the ajax submit.
<script>
$( init );
function init() {
$('#contactForm').submit( submitForm );
}
function submitForm() {
var contactForm = $(this);
if ( !$('#name').val() || !$('#email').val() || !$('#message').val() ) {
$('#submit').html('error');
} else {
$('#submit').html('sending');
$.ajax( {
url: contactForm.attr( 'action' ) + "?ajax=true",
type: contactForm.attr( 'method' ),
data: contactForm.serialize(),
success: submitFinished
} );
}
return false;
}
function submitFinished( response ) {
response = $.trim( response );
if ( response == "success" ) {
$('#submit').HTML = ('sent');
} else {
$('#submit').html('error');
}
}
</script>
the mail.php:
<?php
define( "RECIPIENT_NAME", "John Doe" );
define( "RECIPIENT_EMAIL", "john#doe.com" );
define( "EMAIL_SUBJECT", "Subject" );
$success = false;
$name = isset( $_POST['name'] ) ? preg_replace( "/[^\.\-\' a-zA-Z0-9]/", "", $_POST['name'] ) : "";
$email = isset( $_POST['email'] ) ? preg_replace( "/[^\.\-\_\#a-zA-Z0-9]/", "", $_POST['email'] ) : "";
$message = isset( $_POST['message'] ) ? preg_replace( "/(From:|To:|BCC:|CC:|Subject:|Content-Type:)/", "", $_POST['message'] ) : "";
if ( $name && $email && $message ) {
$recipient = RECIPIENT_NAME . " <" . RECIPIENT_EMAIL . ">";
$headers = "Von: " . $name . " <" . $email . ">";
$success = mail( $recipient, EMAIL_SUBJECT, $message, $headers );
}
if ( isset($_GET["ajax"]) ) {
echo $success ? "success" : "error";
} else {
//add html for javascript off user
}
?>
Its submits correct and i get the mail but i doesnt change the label to sent.Its stuck at sending.
Any idea or suggestions whats wrong with my code?
best regards
dennym

Answer 1

The error is on this line:
$('#submit').HTML = ('sent');
Change that to:
$('#submit').html('sent');

Answer 2

$('#submit').HTML = ('sent');
should be
$('#submit').html('sent');
like you have everywhere else.

Answer 3

You have to change
$('#submit').HTML = ('sent');
to:
$('#submit').html('sent');
in your function submitFinished();