That's why you have to click. Before the a:visited exploit was patched, a simple loop with GetComputedStyle would have sufficed. If you do that in a modern brow

That's why you have to click. Before the a:visited exploit was patched, a simple loop with GetComputedStyle would have sufficed. If you do that in a modern browser, all the squares come back color gray. The content script only gets to see the style attributes as they would be in the unvisited state.