function inicializace() {
  maketargetblank();
}

function maketargetblank() {
  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.getAttribute("rel") == "nofollow")) anchor.target = "_blank";
  }
}