function external() {
 if (document.getElementsByTagName) {
  var i, a;
  a = document.getElementsByTagName('a');
  for (i in a) 
  {
  	try
  	{
  	if (a[i].getAttribute('href') && a[i].getAttribute('rel') == 'external') 
  		a[i].target = '_blank';
  	}
  	catch(Err)
  	{}
  }
 }
}

window.onload = external;