765448 - Setting background-color in an 'a:visited' rule doesn't work

Status: RESOLVED WONTFIX

(Core :: CSS Parsing and Computation, defect)

Description

[mjh563]

Attachment: testcase

The attached testcase sets the color of a ':visited' link to red and the background color to yellow. However, only the text color is applied.

Fails: Firefox 14, Chrome

Works as expected: Firefox 3.6.28, Opera 12

Comment 1

[Boris Zbarsky [:bzbarsky]]

This is expected behavior due to http://dbaron.org/mozilla/visited-privacy

In particular, you're using a solid color for a:visited and a transparent background for unvisited links.  The relevant part of the document linked above is:

   If the relevant link is visited, it returns a color whose R (red), G (green), and B
   (blue) components come from the second style context (the style-if-visited) but whose A
   (alpha) component comes from the first.

And the unvisited style has an alpha of 0, so you get a transparent background.

Which is to say, you should be explicitly specifying backgrounds for unvisited links if you want links to have backgrounds...

Comment 2

[mjh563]

OK, thanks. I wasn't aware of that particular aspect of the :visited history leak fix. As you say, it works if the unvisited link has an explicit (non-transparent) background color set.

Comment 3

[Boris Zbarsky [:bzbarsky]]

Yeah... unfortunately, different alpha values for the two colors are subject to timing attacks, hence the restriction here.