function change_bg(obj) {
	obj.style.backgroundImage = "url('images/menu_selected.gif')";
}

function recover_bg(obj) {
	obj.style.backgroundImage = "";
}

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;