不随页面滚动的元素(<回到顶部>或者是页面顶部信息之类的)
.ToTop{ position: fixed;//类似于absolute,不过其包含块是视窗本身 bottom: 0; background: black; width: 90px; height: 90px; line-height: 23px; z-index: 9999; opacity: 0.6;//Chrome
/*以下针对IE*/ filter: alpha(opacity=60); _bottom: auto; _width: 100%; _position: absolute; _top: expression(eval(document.documentElement.scrollTop+document.documentElement.clientHeight-this.offsetHeight-(parseInt(this.currentStyle.marginTop,10)||0)-(parseInt(this.currentStyle.marginBottom,10)||0))); }