If you go back far enough there weren't even protections against this sort of thing at all! E.g. you could just say a visited link style was 1px taller then mea

If you go back far enough there weren't even protections against this sort of thing at all! E.g. you could just say a visited link style was 1px taller then measure that. The protections had to be added in after the fact (often with special case logic for what's allowed to be styled or read on :visited) once security became a major concern!