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;