Prototype Ajax.Updater not working correctly with delay

What I got here is a Ajax.Updater prototype js function. It's working perfectly this way:

new Ajax.Updater('feedback', 'contact.php', {
    method: 'post',
    parameters: Form.serialize($('contactForm')),
    onFailure: reportError
});

But I want to delay the process a bit. I asked around on the prototype irc channel and this seems the way to go:

var feedback = function() {
    new Ajax.Updater('feedback', 'contact.php', {
        method: 'post',
        parameters: Form.serialize($('contactForm')),
        onFailure: reportError
    });

    new Effect.Highlight('feedback', {
        duration: 1
    });
}
feedback.delay(1.5);

(don t mind the scriptaculous effect)

There is a echo function in contact.php that looks like this:

echo("Thanks for your message $_POST['Name']!");

After applying the delay the name is no longer echoed! What's wrong?

Solution

Ok last try on this one. This works for me and does what you want

My html-file

<html>
    <head>
        <title>asd</title>
        <script type="text/javascript" src="src/prototype.js"></script>
        <script type="text/javascript" src="src/scriptaculous.js"></script>
        <script type="text/javascript">
            var feedback = function() {
                var params = Form.serialize($('contactForm'));
                new Ajax.Updater('feedback', 'contact.php', {
                    method: 'post',
                    parameters: params,
                    onFailure: reportError,
                    asynchronous:true
                });

                new Effect.Highlight('feedback', {
                    duration: 1
                });
            }
            function reportError(request) { alert("error");} 

        </script>
    </head>
    <body>
        <form id="contactForm">
            <p>Name:<br><input name="Name" type="text" size="30" maxlength="30"></p>
            <input name="sendbutton" type="button" value="Send" onClick="feedback.delay(1.5);">
        </form>
        <div id="feedback">foo</div>
    </body>
</html>

My contact.php

<?php
echo("Thanks for your message ".$_POST['Name']."!");
?>

and using the js files from here