// Open new windows

function externallinks () {

   if ( document.getElementsByTagName ) {

      var links = document.getElementsByTagName ( 'a' );

      for (var i = 0; i < links.length; i++ ) {

         var link = links[i];

         if ( ( link.getAttribute ( 'href' ) ) && ( link.getAttribute ( 'rel' ) == 'external' ) ) {

            link.target = '_blank';

         }

      }

   }

}

function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

addLoadEvent(externallinks);