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

 	for (var i=0; i<anchors.length; i++)
 	{
   		var anchor = anchors[i];
   		if (anchor.getAttribute("href") && anchor.getAttribute("rel") == "external") anchor.target = "_blank";
 	}
}

window.onload = externalLinks;