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;