changing an elements css position after scrolling down the page

Question

I am messing around with some jquery trying to get to grips with it.

I have a ul nav which has a absolute position set but after I scroll the page down by 200 pixels

Answer 1

Thanks to everyone for being so quick to help

this is what i wanted

$(document).ready(function() {
    var theLoc = $('ul').position().top;
    $(window).scroll(function() {
        if(theLoc >= $(window).scrollTop()) {
            if($('ul').hasClass('fixed')) {
                $('ul').removeClass('fixed');
            }
        } else { 
            if(!$('ul').hasClass('fixed')) {
                $('ul').addClass('fixed');
            }
        }
    });
});

i got it from

http://www.defringe.com/

http://satbulsara.com/tests/

Thankss!!!!!