Set Div Position to Fixed when Scroll using jQuery

Hi,

I have a simple View which have 3 line Div.

I just need help how to setting when i scroll up and down the overflow page header must keep on show.

<div>header line</div>
<div id =sticky>
  <div>line 1</div>
  <div>line 2</div>
</div>
<script type="text/javascript">
    var stickyOffset = $('.sticky').offset().top;
    $(window).scroll(function () {
        var sticky = $('.sticky'),
        scroll = $(window).scrollTop();
        if (scroll >= stickyOffset) sticky.addClass('fixed');
        else sticky.removeClass('fixed');
    });
</script>