Ketchup formvalidation fails, form submits

Ketchup formvalidation fails, form submits

Hello,
I just added form validation with the ketchup plugin.
The validation fails, but the page gets anyway submitted to the server, which is in my case a 4D database.
I'm sure I'm missing something or doing something wrong, as the examples are all working …
The code looks like this:
<head>
(…)
<script type="text/javascript">                       
    $(document).ready(function() {
    $('#contactForm').ketchup();
});
</script></head>
<body>
blabla
<form action=„/4DCGI/WWW_Contact" method="post" name="contactForm" id="contactForm">
    <label for="db-mail">E-Mail</label> <input type=„text" id="db-mail" data-validate="validate(required, email)" />
    <input value=„Send Message" title="send" class="contact-submit submit" id="send" type="submit" />
</form>
blabla
</body>
thanks
quwax