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;