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;