function externalLinks(){
 if (!document.getElementsByTagName) return;
 var anchors = document.getElementsByTagName("a");
 for (var i=0; i<anchors.length; i++) {
 var anchor = anchors[i];
 var relvalue = anchor.getAttribute("rel");
 if (anchor.getAttribute("href")) {
 var external = /external/;
 var relvalue = anchor.getAttribute("rel");
 if (external.test(relvalue)) { anchor.target = "_blank"; }
 }
}
}
window.onload = externalLinks;