You can target an element that has no child elements by using the :empty pseudo-class. With browser support down to IE9, it's solid, easy way to select empty elements without any additional markup. Be aware that whitespace is considered a "child"
CSS的positon,我想做为一个Web制作者来说都有碰到过,但至于对其是否真正的了解呢?那我就不也说了,至少我自己并不非常的了解其内核的运行.今天在Learn CSS Positioning in Ten Steps一文中分十步介绍了CSS的"position"中的"static.relative.absolute.float"使用,觉得蛮有意思的.整理了一下贴上来与大家一起分享.希望大家能喜欢. 在图解这十个过程之前,我将实例的代码放上来,好让大家一个实体参考