window.onload = function() {
var links = document.getElementsByTagName("a");
for (var i = 0; i < links.length; i++) {
  var rels = links[i].getAttribute("rel");
  if (rels) {
	var testpattern = new RegExp("external");
	if (testpattern.test(rels)) {
	  links[i].onclick = function() {
		return !window.open(this.href);  
	  }
	}
  }    
}
}