background-image: for :visited links?

问题:

Is it possible to add the background-image: property to visited links?

 a.coolLinks:visited{
     background-image:url("http://www.ledr.com/colours/black.jpg");
}

Thanks

Edit: So it appears that this is a security vulnerability and this is why it cannot be done. There was no indication that the browsers were blocking this css style.

回答1:

Your code is correct according to most specifications. However, many browsers consider background images on visited links a potential violation of user's privacy, so they do not allow it.

Observe this example:

<p><a href="/unvisited">Unvisited link</a></p>

<p><a href="http://jsfiddle.net/">Visited Link</a></p>

<style>
a {
  background:red url("http://placekitten.com/100/101?image=2") center center no-repeat;
  display: block;
  height: 200px;
  width: 200px;
  overflow: hidden;
  text-align: center;
  background-color: red;
}

a:visited {
  background:blue url("http://placekitten.com/100/100?image=1") center center no-repeat;
}
</style>

(Also at http://jsfiddle.net/Yq5GY/1/). Firefox ignores the background image declaration for visited links, and never displays the solo kitten. You can do some differentiation with background color. It's bad usability to rely on images alone, anyhow.

回答2:

MDN spec for :visited, you will notice background-image is not allowed.

回答3:

As @KatieK suggested, most browser would not allow setting a background-image [even some other rules like background-color] to :visited links as it is a Privacy Problem. You can read about it using the following links:

1. Privacy Related Changes
2. Reported Bug