var doneLink = [];
function linkTargets () {
  $$('a').each(function (a) {
    if (!doneLink.member(a) && a.getAttribute('href') && a.getAttribute('rel')) {
      a.target = a.getAttribute('rel');
			doneLink.push(a);
    }
  });
}
Event.observe(window, 'load', linkTargets);