function targetBlank(event) { 
  event = event ? event : window.event; 
  var target = event.srcElement ? event.srcElement : event.target; 
  while (target.nodeName.toLowerCase() != "a" && target.parentNode != null) 
    target = target.parentNode; 
  window.open(target.getAttribute("href"), "_blank"); 
  // DOM 
  if (event.cancelable) 
    event.preventDefault(); 
  // IE 
    return false; 
  } 
  
function targetBlankBind() { 
  var tags = document.getElementsByTagName("A"); 
  var i; for (i=0; i<tags.length; i++) 
  if (tags[i].getAttribute("rel") == "external") 
    tags[i].onclick = targetBlank; 
  } 

if (window.attachEvent) { 
  // IE 
  window.attachEvent("onload", targetBlankBind); 
  } 
else { 
  // DOM 
  window.addEventListener("load", targetBlankBind, false); 
  }