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;