Detect Visited Link In Chrome

I am using a userscript for Chrome and Firefox and I am checking for links that have been visited by the user. I have a{ color: blue; } a:visited{ color: red !important; }

Solution 1:

A_horse_with_no_name is right. The :visited security issue was fixed in 2010 by the browser vendors, after a nifty demo (Spyjax; no longer up) demonstrated that any webpage could discover whether you've visited any given URL. You can verify that getComputedStyle on a link no longer returns the :visited color--even within the same domain:

// Test I used within the JS console.
// :visited is no longer detectable by getComputedStyle.
function getLinkColor(url) {
  var a = document.createElement('a');
  a.href = a.textContent = url;
  document.body.appendChild(a);
  return document.defaultView.getComputedStyle(a, null).color;
}
getLinkColor('http://stackoverflow.com/questions/5394099/detect-visited-link-in-chrome');
getLinkColor('http://stackoverflow.com/some-fake-path');

For Chrome extensions, if you want to detect whether a user has visited a URL, I think you'll have to request the "history" permission and call chrome.history.getVisits.