本文实例讲述了jQuery实现返回顶部效果的方法。分享给大家供大家参考。具体实现方法如下：
1、首先是CSS样式：
/*updown*/
#shangxia{position:fixed;top:83%;right:42%;margin-right:-543px;display:block;_display:none}
#shang,#comt,#xia{background:url(../images/sprite.png) no-repeat;position:relative;cursor:pointer;height:25px;width:29px;margin:10px 0 0}
#shang{background-position:0 -308px}#comt{background-position:0 -338px;height:32px}
#xia{background-position:0 -376px}
#comt:hover{background-position:-31px -338px}#shang:hover{background-position:-31px -308px}
#xia:hover{background-position:-31px -376px}
2、接着是jquery代码：（要引入jQuery核心库）
jQuery(document).ready(function($) {$body = (window.opera) ? (document.compatMode == "CSS1Compat" ? $("html") : $("body")) : $("html,body");$("#shang").mouseover(function() {up()}).mouseout(function() {clearTimeout(fq)}).click(function() {$body.animate({scrollTop: 0},400)});$("#xia").mouseover(function() {dn()}).mouseout(function() {clearTimeout(fq)}).click(function() {$body.animate({scrollTop: $(document).height()},400)});$("#comt").click(function() {$body.animate({scrollTop: $("#comments").offset().top},400)});});function up() {$wd = jQuery(window);$wd.scrollTop($wd.scrollTop() - 1);fq = setTimeout("up()", 50)};function dn() {$wd = jQuery(window);$wd.scrollTop($wd.scrollTop() + 1);fq = setTimeout("dn()", 50)};
3、引用页面：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<style type="text/css">
/*updown*/
#shangxia{position:fixed;top:60%;right:50%;margin-right:-543px;display:block;_display:none}
#shang,#comt,#xia{background:url(images/sprite.png) no-repeat;position:relative;cursor:pointer;height:25px;width:29px;margin:10px 0 0}
#shang{background-position:0 -308px}#comt{background-position:0 -338px;height:32px}#xia{background-position:0 -376px}
#comt:hover{background-position:-31px -338px}#shang:hover{background-position:-31px -308px}#xia:hover{background-position:-31px -376px}
/*存档*/
</style>
///上面的是内部样式，上面已经有外部样式，如果不使用内部样式可以引入外部样式
<script type="text/javascript" src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<script type="text/javascript" src="http://code.jquery.com/jquery-migrate-1.2.1.min.js"></script>
<script type="text/javascript" src="js/updown/devework.js"></script>
</head>
<body>
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<div id="shangxia">
<div id="shang" title="↑ 返回顶部"></div>
<div id="comt" title="沙发还没有被抢哦"></div>
<div id="xia" title="↓ 移至底部"></div>
</div>
</body>
</html>
希望本文所述对大家的jQuery程序设计有所帮助。