jQuery返回顶部（精简版）
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>jQuery返回顶部</title> <style> *body{ background-attachment: fixed; background-image: url(about:blank); /* 必须的，防抖动 */} *body #toTop{ position: absolute; top:expression(eval(document.documentElement.scrollTop+document.documentElement.clientHeight-this.offsetHeight-10)); /* 底部固定悬浮 */} #toTop{ display: none; position: fixed; border: 1px solid red; right: 10px; bottom: 10px; padding: 10px 0; cursor: pointer;} </style> </head> <body style="height:3000px;"> <div id="toTop"> scroll to top</div> <script src="http://apps.bdimg.com/libs/jquery/1.9.1/jquery.js"></script> <script> $(function(){ var toTop = $('#toTop'); // 当窗口滚动条滚动时触发 $(window).scroll(function(){ var st = $(window).scrollTop(); //获取浏览器窗口向上滚动的距离 // 选项卡标签栏/控制台调试代码 // document.title = $(window).scrollTop(); // console.log($(window).scrollTop()); // 判断向上滚动距离是否大于500 if(st<500){ toTop.fadeOut('fast'); }else{ toTop.fadeIn('fast'); } }); // 当点击按钮时触发 toTop.click(function(){ $('html ,body').animate({ scrollTop: 0 },300); return false; }); }); </script> </body> </html>