externalLinks = function() {
 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";
 }
}

if (window.addEventListener)
	window.addEventListener("load", externalLinks, false);
else if (window.attachEvent)
	window.attachEvent("onload", externalLinks);