prototype.js 1.4 原代码阅读

      var pair = [key, value];
      pair.key = key;
      pair.value = value;
      iterator(pair);
    }
  },

  keys: function() {
    return this.pluck('key');
  },

  values: function() {
    return this.pluck('value');
  },

  merge: function(hash) {
    return $H(hash).inject($H(this), function(mergedHash, pair) {
      mergedHash[pair.key] = pair.value;
      return mergedHash;
    });
  },

  toQueryString: function() {
    return this.map(function(pair) {
      return pair.map(encodeURIComponent).join('=');
    }).join('&');
  },

  inspect: function() {
    return '#<Hash:{' + this.map(function(pair) {
      return pair.map(Object.inspect).join(': ');
    }).join(', ') + '}>';
  }
}

function $H(object) {
  var hash = Object.extend({}, object || {});
  Object.extend(hash, Enumerable);
  Object.extend(hash, Hash);
  return hash;
}
ObjectRange = Class.create();
Object.extend(ObjectRange.prototype, Enumerable);
Object.extend(ObjectRange.prototype, {
  initialize: function(start, end, exclusive) {
    this.start = start;
    this.end = end;
    this.exclusive = exclusive;
  },

  _each: function(iterator) {
    var value = this.start;
    do {
      iterator(value);
      value = value.succ();
    } while (this.include(value));
  },

  include: function(value) {
    if (value < this.start)
      return false;
    if (this.exclusive)
      return value < this.end;
    return value <= this.end;
  }
});

var $R = function(start, end, exclusive) {
  return new ObjectRange(start, end, exclusive);
}

/**
 * 定义 Ajax 对象, 静态方法 getTransport 方法返回一个 XMLHttp 对象
 */
var Ajax = {
  getTransport: function() {
    return Try.these(
      function() {return new XMLHttpRequest()},
      function() {return new ActiveXObject('Msxml2.XMLHTTP')},
      function() {return new ActiveXObject('Microsoft.XMLHTTP')}
    ) || false;
  },

  activeRequestCount: 0
}

Ajax.Responders = {
  responders: [],

  _each: function(iterator) {
    this.responders._each(iterator);
  },

  register: function(responderToAdd) {
    if (!this.include(responderToAdd))
      this.responders.push(responderToAdd);