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.getAttribute("target") != "_blank"){
		 var ext = anchor.cloneNode(false);  
		 var image = document.createElement('img');
		 image.src = "/images/external.png";
		 ext.appendChild(image);
     ext.target = "_blank";
		 anchor.parentNode.insertBefore(ext,anchor.nextSibling);
	 }
 }
}

window.onload = externalLinks;