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";
	  }
    }
}