Faites défiler le style
<script type="text/javascript">
$window.scrollTop(function(){
var a = 112;
var pos = $window.scrollTop();
if(pos > a) {
$("menu").css({
position: 'fixed'
});
}
else {
$("menu").css({
position: 'absolute',
top:'600px'
});
}
});
</script>
Gifted Gharial