prototype.js 1.4 原代码阅读

document.getElementsByClassName = function(className, parentElement) {
  var children = ($(parentElement) || document.body).getElementsByTagName('*');
  return $A(children).inject([], function(elements, child) {
    if (child.className.match(new RegExp("(^|\\s)" + className + "(\\s|$)")))
      elements.push(Element.extend(child));
    return elements;
  });
}

/*--------------------------------------------------------------------------*/

if (!window.Element)
  var Element = new Object();

Element.extend = function(element) {
  if (!element) return;
  if (_nativeExtensions) return element;

  if (!element._extended && element.tagName && element != window) {
    var methods = Element.Methods, cache = Element.extend.cache;
    for (property in methods) {
      var value = methods[property];
      if (typeof value == 'function')
        element[property] = cache.findOrStore(value);
    }
  }

  element._extended = true;
  return element;
}

Element.extend.cache = {
  findOrStore: function(value) {
    return this[value] = this[value] || function() {
      return value.apply(null, [this].concat($A(arguments)));
    }
  }
}

Element.Methods = {
  visible: function(element) {
    return $(element).style.display != 'none';
  },

  toggle: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      Element[Element.visible(element) ? 'hide' : 'show'](element);
    }
  },

  hide: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      element.style.display = 'none';
    }
  },

  show: function() {
    for (var i = 0; i < arguments.length; i++) {
      var element = $(arguments[i]);
      element.style.display = '';
    }
  },

  remove: function(element) {
    element = $(element);
    element.parentNode.removeChild(element);
  },

  update: function(element, html) {