Why doesn't checkmark appear before visited links?

Question

There are many examples of the following before pseudo technique. But for whatever reason, I'm not seeing the checkmark in Safari and Chrome. Anyone know what is wrong?

CSS

a:visited:before {
 content:  "\2713 ";
}

Webpage content

 <a href="http://www.microsoft.com" target="_blank">is a link</a>

http://jsfiddle.net/NG5KX/1/

Answer 1

Styling for :visited has been significantly curtailed to prevent security loopholes, see this this from mozilla

Indeed, :visited and :link items can only be styled by color (SEC7115)

Answer 2

This is because it was almost remove (but some styles such as colors) to prevent security flaws. It was possible to read your whole browser history with.

A small script could easily create links and then check if it has been visited by looking at the style.

More explanation :

• http://www.theregister.co.uk/2010/12/03/browser_history_sniffing/
• http://krebsonsecurity.com/2010/12/what-you-should-know-about-history-sniffing/