Jquery jitter ie

I'm using this code but in Internet Explorer causes the header which follows the page scroll to act very jittery. Anyone know what problem could be?

var name = "#header";  
var menuYloc = 'null'; 

menuYloc = parseInt($(name).css("top").substring(0,$(name).css("top").indexOf("px")))           
$(window).scroll(function () {  
    var offset = menuYloc+$(window).scrollTop()+"px";  
    alert(offset);
       $(name).animate({'top':开发者_高级运维offset},500);  
});  

I think you are trying to scroll the #header along with the scroll. It can be acheived by simple css.

#header
{
   position:fixed;
}