让浮动的图层固定在顶部，滚动条下翻时层不闪动的特效-JS特效-爱易网页

让浮动的图层固定在顶部，滚动条下翻时层不闪动的特效

日期：2014-05-18　浏览次数：20234 次

以下是程序代码

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
body{ padding:0; margin:0;}
#main{width:800px; height:4200px; margin: 0 auto; background:#9CC; position:relative; }
#other{clear:both; height:128px;}
#box{width:560px; height:45px; background:#39C; margin:0 auto; position:absolute; top:128px; left:120px}
</style>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js"></script>
<script type="text/javascript">
 $(function(){ 
  $(window).scroll(function(){
   
   boxY = $('#box').offset().top;
   $("#box").text(boxY);
   yy = $(this).scrollTop();
   xx = $(this).width();
   //alert(xx);
   boxXX = xx / 2 - 280;
   if ($(this).scrollTop() > 128) {
     
    $('#box').css({"position":"fixed",top:"0px",left:boxXX + "px"});
   // $('#box').animate({top:yy+"px"},28);
    
   } else {
    
    $('#box').css({"position":"absolute",top:"128px",left:"120px"});
    
   }
   
  })
 
 
 })
</script>
</head>
<body>
<div id="main">
 <div id="other"></div>
 <div id="box"></div>
</div>
</body>
</html>

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