[置顶]       jquery返回页面顶部

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>