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;

function showElement(layer){
var myLayer = document.getElementById(layer);
if(myLayer.style.display=="none"){
myLayer.style.display="block";
myLayer.backgroundPosition="top";
} else {
myLayer.style.display="none";
}
}