addEvent(window, 'load', external_links);

function external_links() {
	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';
		}
	}
}