gistfile1.txt

<style>
a.tracklink:visited {color:black!important;display:none;}
a.tracklink:link {color:white!important;;display:none;}
</style>
<script>
        function isVisited(url) {
          var link_el = document.createElement('a');
          link_el.innerHTML = "-";
          link_el.className = "tracklink";
          link_el.href = url;
          document.body.appendChild(link_el);
          var computed_style = document.defaultView.getComputedStyle(link_el, "");
          if (computed_style.getPropertyValue("color") == 'rgb(0, 0, 0)') {
            return true;
          }
          return false;
        }
</script>