[jQuery] error jquery-1.3.2.js(line 3633)

[Mark]

I have 3 drop down menu's where is post the value's bij a button.click
(see code below).
But when i push the button i see an error in fire bug "POST"
http://localhost/agenda nieuw/handler.php 67ms  jquery-1.3.2.js(line
3633)"
I looked online for awnsers but couldn't find any. Maybe you guys can
help me. Here is my js code.

<script type="text/javascript" src="jquery-1.3.2.js"></
script>
<script type="text/
javascript">

    $(document).ready(function() {
                $("button").click(function() {
                        $.post('handler.php', {

                                jaar:$('#jaar').val(),//jaar means year
                                maand:$('#maand').val(),//maand means month
                                week:$('#week').val(),

                        })
                });
        });
</script>