清除Html元素浮动
html body div.clear, html body span.clear { background: none; border: 0; clear: both; display: block; float: none; font-size: 0; margin: 0; padding: 0; overflow: hidden; visibility: hidden; width: 0; height: 0; }
html body div.clear, html body span.clear { background: none; border: 0; clear: both; display: block; float: none; font-size: 0; margin: 0; padding: 0; overflow: hidden; visibility: hidden; width: 0; height: 0; }