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;