function externalLinks() {
          if (!document.getElementsByTagName) return;
          var anchors = document.getElementsByTagName("a");
          for (var i=0; i<anchors.length; i++) {
            var anchor = anchors[i];
            if (anchor.getAttribute("href") && anchor.getAttribute("rel") == "external")
              anchor.target = "_blank";
          }
        }
        window.onload = externalLinks;