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;