function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      oldonload();
      func();
    }
  }
}

addLoadEvent(externalLinks);

function externalLinks() {
	if (!document.getElementsByTagName) return;
	var anchors = document.getElementsByTagName("a");

	for (var i=0; i<anchors.length; i++) {
	//for (var i= anchors.length; i>0; i--) {
		
		rel = anchors[i].getAttribute("rel");
		
		if (anchors[i].getAttribute("href") && rel && rel.indexOf("external") != -1)
		{
	      	anchors[i].target = "_blank";
		}
	}
}