1.样式设置
#toTop { /*选中的背景图片的大小*/ width: 54px; height: 54px; display: none;/*刚开始不显示*/ position: fixed; right: 25px;/*距离右边大小值*/ bottom: 45px;/*距离底部大小值*/ /*选定图片区域*/ background-image: url(images/qqbg_1.5.5.png); background-repeat: no-repeat; background-position: -700px -110px; opacity: 0.3; /*透明度*/ } #toTop:hover { opacity: 1;/*悬停时不透明*/ filter: alpha(opacity = 100); }
2.js代码
<a href="#" target="_self" id="toTop" title="返回顶部" onclick="window.scrollTo(0,0);return false"></a> <script type = "text/javascript"> function toTopHide(){ $(document).scrollTop()>400? $("#toTop").show() :$("#toTop").hide(); } $(window).scroll(function(){toTopHide()}); </script>
