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") == "blank nofollow")||(anchor.getAttribute("rel") == "nofollow blank")||(anchor.getAttribute("rel") == "blank")))
anchor.target = "_blank";  
}  
}  
window.onload=externalLinks;