document.onclick = function(e)

{

  var target = e ? e.target : window.event.srcElement;

  while (target && !/^(a|body)$/i.test(target.nodeName))

  {

    target = target.parentNode;

  }

  if (target && target.getAttribute('rel') && target.rel == 'external')

  {

    var external = window.open(target.href);

    return external.closed;

  }

}