function extLinks(c)
 {
   if((c == undefined) || (c == '')) c = 'external';
   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.className.indexOf(c) >= 0)
         {
           anchor.target = "_blank";
         }
   }
 }
 
 window.onload=function(){ extLinks(); }