function link_target() {
	if (!document.getElementsByTagName) return;   // check browser
 		var anchors = document.getElementsByTagName("a"); // find all a tags
 		for (var i=0; i<anchors.length; i++) {
   		var anchor = anchors[i];
   		if (anchor.getAttribute("href") &&
       			anchor.getAttribute("rel") == "external"){
     			anchor.target = "_blank";
		}
	}
}