// externe links
function externalLinks() {
   if (!document.getElementsByTagName) return;
   var anchor, anchors = document.getElementsByTagName("a");
   for (var i=0; i<anchors.length; i++) {
      anchor = anchors[i];
      if (anchor.getAttribute("rel") == "external") {
         anchor.onclick = function() {
            window.open(this.getAttribute('href'));
            return false;
         }
      }
   }
}
window.onload = externalLinks;