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") == "sweetheart")   
anchor.target = "_blank";   
}   
}   
window.onload=externalLinks;