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") == "top")
   anchor.target = "_top";
  else if (anchor.getAttribute("href") && anchor.getAttribute("rel") == "blank")
   anchor.target = "_blank";
 }
}
window.onload = externalLinks;