.backToTop { display: none; width: 18px; line-height: 1.2; padding: 5px 0; background-color: #000; color: #fff; font-size: 12px; text-align: center; position: fixed; _position: absolute; right: 10px; bottom: 100px; _bottom: "auto"; cursor: pointer; opacity: .6; filter: Alpha(opacity=60);}
JS代码:
(function() { var $backToTopTxt = "返回顶部", $backToTopEle = new Element("div", { "class": "backToTop", title: $backToTopTxt }).set("text", $backToTopTxt).addEvent("click", function() { var st = document.getScroll().y, speed = st / 6; var funScroll = function() { st -= speed; if (st <= 0) { st = 0; } window.scrollTo(0, st); if (st > 0) { setTimeout(funScroll, 20); } }; funScroll(); }).inject(document.body), $backToTopFun = function() { var st = document.getScroll().y, winh = window.getSize().y; (st > 0)? $backToTopEle.setStyle("display", "block"): $backToTopEle.setStyle("display", "none"); if (!window.XMLHttpRequest) { $backToTopEle.setStyle("top", st + winh - 166); } }; window.addEvents({ scroll: $backToTopFun, domready: $backToTopFun });})();