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')||anchor.getAttribute('className'))=='ext')
      anchor.target = "_blank";
  }
}

try{
	window.addEventListener("load",externalLinks,false);
}catch(e){
	window.attachEvent("onload",externalLinks);
}