源码搜藏网

<script type="text/javascript">
$(function(){

if ($.browser.msie && ($.browser.version == "6.0") && !$.support.style) {
var handler,sTop,dTop;
				dTop = $("#fixedNav").offset().top
    $(window).bind('scroll',function(){
        window.clearTimeout(handler);
        handler = window.setTimeout(function(){
            sTop = $(document).scrollTop();
            sTop > dTop  $("#fixedNav").css("top",sTop - dTop) : $("#fixedNav").css("top",0);
	    $("#fixedNav").css({"position":"relative","z-index":"1200"});
        },60);
    });
}else{

	var topMain= $("#fixedNav").offset().top
 $(window).scroll(function(){
  if ($(window).scrollTop()>topMain){
   $("#fixedNav").addClass("nav_scroll");
  }else{
   $("#fixedNav").removeClass("nav_scroll");
  }
 });

	}
});
</script>

.nav_scroll{ position:fixed;top:0;left:0;z-index:1200; width:100%;}