// JavaScript Document
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("class") == "extern") {
      anchor.target = "_blank";
    }
  }
}