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;