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;