dynamically add methods

เห็นวิธี add dynamic method ของ Prototype แล้วชอบใจดี

var Iterators = function() {
  var tags = "div p span ul ol li span form input select textarea h1 h2 h3 h4 h5 h6 dl dt em strong";
  var methods = {};
  $A(tags.split(' ')).each(function(tag) {
    methods["each" + tag.charAt(0).toUpperCase() + tag.substring(1)] = function(element, iterator) {
      element = $(element);
      element.cleanWhitespace();
      $A(element.getElementsByTagName(tag)).each(iterator);
    }
  });

  Element.addMethods(methods);
}();

Writing Custom Iterators For Prototype