function setExternalLinks() {
     if (!document.getElementsByTagName) {
         return null;
     }
     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.setAttribute("target", "blank");
         }
     }
 }
window.onload = setExternalLinks;