External Links on Xaraya.com

I'm curious as to how the external links work on Xaraya.com.  I know it 
uses rel="external" in the links and I know it uses the js:

setExternalLinks=function() {
     if ( !document.getElementsByTagName ) {
         return null;
     }

     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.setAttribute( "target", "_blank" );
         }
     }
}


What am I missing?   :/