var name = "#float";  
var menuYloc = null;  
      
$(document).ready(function()
{  
  menuYloc = parseInt($(name).css("top").substring(0,$(name).css("top").indexOf("px")))  
  $(window).scroll(function()
  {  
    var offset = menuYloc+$(document).scrollTop()+"px";  
    $(name).animate({top:offset},{duration:500,queue:false});  
  });  
});