function linkExterno()
{

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") == "http://www.flickr.com" || anchor.getAttribute("rel") == "externo")
    {
    anchor.target = "_blank";
    }
  }

}

window.onload = linkExterno ;