左岸16
<style type="text/css">
*{margin:o;padding:0;}
body{font-size:12px;}
#div1{
width:200px;height:200px;background:purple;
position:relative;left:-200px;top:0;
}
#div1 span{
width:20px;height:50px;background:red;
position:absolute;left:200px;top:75px;
}
</style><body>
<div id="div1">关于滚动条滚动的距离有两种模式即混杂模式document.body.scrollTop和标准模式document.documentElement.scrollTop。<span id="share">分享</span></div>
</body>