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

 } 
} 
window.onload = externalLinks;