无法更改已访问的内容：before伪元素
我试图为访问过的链接添加一些效果，然后我遇到这个问题。
I was trying to add some effects for visited links, then I got this problem.
这是代码： http://dabblet.com/gist/5447894
只有Opera可以成功更改内容的：before 伪元素。所有其他浏览器都失败。我错过了什么吗？感谢
Only Opera can successfully change the content of :before pseudo-elements. All other browsers are fail. Did I miss anything? Thanks
访问过的链接的允许（=未忽略）CSS属性是 color ， background-color ， border - * - color ， / code>和 column-rule-color （在某些情况下更多）。
The allowed (= not ignored) CSS properties of visited links are color, background-color, border-*-color, outline-color and, column-rule-color (more under certain circumstances).
防止历史窃取攻击。有关详情，请参见本文。
This is to prevent history stealing attacks. See this article for further details.
因此，您可以在技术上为：visited 链接设置：之前伪类，忽略并且看起来好像未访问链接。这不是一个错误，它是一个功能;）
So you can, technically, set a :before pseudo class for :visited links, but it will be ignored and appears as if the links are not visited. This is not a bug, it's a feature ;)