jQuery doesn't work on my server but does work in jsfiddle
<p>This is starting to freak my out by now. What's happening here?</p>

<p>See no result on <a href="http://www.mauricekappelhof.nl/work/TemplateTest/Backend/menu.php?page=1">http://www.mauricekappelhof.nl/work/TemplateTest/Backend/menu.php?page=1</a>
See working result on <a href="http://jsfiddle.net/x7bgF/">http://jsfiddle.net/x7bgF/</a></p>

<p>Oh, i want to replace spaces with an underscore. So if you type a space in the 'Titel' field, the 'link' field suppose to show the same, but then with an underscore.</p>

<p>It's about this piece of jQuery</p>

<pre><code> $(document).ready(function(){
        $('#title').keyup(function(e){
            var e = e || window.event;
            $('#link').val($(this).val().replace(/\s/g, '_'));
        });​
    });</code></pre>
