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;