// Smart getElementById (taken from prototype library)
function $() {
      var results = [], element;
      for (var i = 0; i < arguments.length; i++) {
        element = arguments[i];
        if (typeof element == 'string')
          element = document.getElementById(element);
        results.push(Element.extend(element));
      }
      return results.length < 2 ? results[0] : results;
}