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.target = "_blank"; 
 	} 
} 
window.onload = externalLinks;