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