// http://www.sitepoint.com/article/standards-compliant-world/3/
<!--

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") == "downloads")
     anchor.target = "downloads";
   if (anchor.getAttribute("href") &&
       anchor.getAttribute("rel") == "_blank")
     anchor.target = "_blank";
   if (anchor.getAttribute("href") &&
       anchor.getAttribute("rel") == "pdf")
     anchor.target = "pdf";
   if (anchor.getAttribute("href") &&
       anchor.getAttribute("rel") == "website")
     anchor.target = "website";
 }
}

if (window.attachEvent) {window.attachEvent('onload', externalLinks);}
else if (window.addEventListener) {window.addEventListener('load', externalLinks, false);}
else {document.addEventListener('load', externalLinks, false);} 
//-->