function externalLinks() {
	if (!document.getElementsByTagName) { return; }
	
 	var aAnchors = document.getElementsByTagName("a");
 	for (var i = 0; i < aAnchors.length; i++) {
   	var oAnchor = aAnchors[i];
   	if (oAnchor.getAttribute("href") && (oAnchor.getAttribute("rel") == "external")) { oAnchor.target = "_blank"; }
 	}
}

window.onload = externalLinks;