jQuery实现返回顶部效果的方法

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）

代码如下:

/*updown*/ 
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>
  <p>1</p>
  <p>1</p>
   <p>1</p>
   <p>1</p>
    <p>1</p>
    <p>1</p>
  <p>1</p>
   <p>1</p>
   <p>1</p>
    <p>1</p>
    <p>1</p>
  <p>1</p>
   <p>1</p>
   <p>1</p>
    <p>1</p>
    <p>1</p>
  <p>1</p>
   <p>1</p>
   <p>1</p>
    <p>1</p>
    <p>1</p>
  <p>1</p>
   <p>1</p>
   <p>1</p>
    <p>1</p>
    <p>1</p>
  <p>1</p>
   <p>1</p>
   <p>1</p>
    <p>1</p>
    <p>1</p>
  <p>1</p>
   <p>1</p>
   <p>1</p>
    <p>1</p>
    <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
       <p>333</p>
    <p>333</p>
     <p>333</p>
     <p>333</p>
      <p>333</p>
      <p>333</p>
       <p>333</p>
    <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。