方法：
在<body>
</body>中添加如下代码：
<a name="top"></a>
<a href="#top">点我返回顶部</a>
整体示例代码如下：
方法：
在<body>
</body>中添加如下代码：
<a name="top"></a>
<a href="#top">点我返回顶部</a>
整体示例代码如下：
<html>
<body>
<a name="top"></a>
<script type="text/javascript">
var x = navigator;
document.write("CodeName=" + x.appCodeName);
document.write("<br />");
document.write("MinorVersion=" + x.appMinorVersion);
document.write("<br />");
document.write("Name=" + x.appName);
document.write("<br />");
document.write("Version=" + x.appVersion);
document.write("<br />");
document.write("CookieEnabled=" + x.cookieEnabled);
document.write("<br />");
document.write("CPUClass=" + x.cpuClass);
document.write("<br />");
document.write("OnLine=" + x.onLine);
document.write("<br />");
document.write("Platform=" + x.platform);
document.write("<br />");
document.write("UA=" + x.userAgent);
document.write("<br />");
document.write("BrowserLanguage=" + x.browserLanguage);
document.write("<br />");
document.write("SystemLanguage=" + x.systemLanguage);
document.write("<br />");
document.write("UserLanguage=" + x.userLanguage);
document.write("CodeName=" + x.appCodeName);
document.write("<br />");
document.write("MinorVersion=" + x.appMinorVersion);
document.write("<br />");
document.write("Name=" + x.appName);
document.write("<br />");
document.write("Version=" + x.appVersion);
document.write("<br />");
document.write("CookieEnabled=" + x.cookieEnabled);
document.write("<br />");
document.write("CPUClass=" + x.cpuClass);
document.write("<br />");
document.write("OnLine=" + x.onLine);
document.write("<br />");
document.write("Platform=" + x.platform);
document.write("<br />");
document.write("UA=" + x.userAgent);
document.write("<br />");
document.write("BrowserLanguage=" + x.browserLanguage);
document.write("<br />");
document.write("SystemLanguage=" + x.systemLanguage);
document.write("<br />");
document.write("UserLanguage=" + x.userLanguage);
document.write("CodeName=" + x.appCodeName);
document.write("<br />");
document.write("MinorVersion=" + x.appMinorVersion);
document.write("<br />");
document.write("Name=" + x.appName);
document.write("<br />");
document.write("Version=" + x.appVersion);
document.write("<br />");
document.write("CookieEnabled=" + x.cookieEnabled);
document.write("<br />");
document.write("CPUClass=" + x.cpuClass);
document.write("<br />");
document.write("OnLine=" + x.onLine);
document.write("<br />");
document.write("Platform=" + x.platform);
document.write("<br />");
document.write("UA=" + x.userAgent);
document.write("<br />");
document.write("BrowserLanguage=" + x.browserLanguage);
document.write("<br />");
document.write("SystemLanguage=" + x.systemLanguage);
document.write("<br />");
document.write("UserLanguage=" + x.userLanguage);
document.write("CodeName=" + x.appCodeName);
document.write("<br />");
document.write("MinorVersion=" + x.appMinorVersion);
document.write("<br />");
document.write("Name=" + x.appName);
document.write("<br />");
document.write("Version=" + x.appVersion);
document.write("<br />");
document.write("CookieEnabled=" + x.cookieEnabled);
document.write("<br />");
document.write("CPUClass=" + x.cpuClass);
document.write("<br />");
document.write("OnLine=" + x.onLine);
document.write("<br />");
document.write("Platform=" + x.platform);
document.write("<br />");
document.write("UA=" + x.userAgent);
document.write("<br />");
document.write("BrowserLanguage=" + x.browserLanguage);
document.write("<br />");
document.write("SystemLanguage=" + x.systemLanguage);
document.write("<br />");
document.write("UserLanguage=" + x.userLanguage);
</script>
<a href="#top">点我返回顶部</a>
</body>
</html>
//部分代码参考w3school