信任的preciously接受的答案居然让我到一点点麻烦。似乎有不只是原型相关的差异更多的事情。我所发现的是，

Trusting the preciously accepted answer actually got me into a little bit of trouble. There seems to be more going on than just prototype-related differences. What I've found is that

的hasOwnProperty不能用，看看是否有键按下present中时关键是引用类型的词典，但在操作员可以。

下面是一个例子来说明。

Here's an example to demonstrate.

code：

var test:Function = function(key:*,label:String):void
    {
        var d:Dictionary = new Dictionary(true);
        d[key] = true;
        trace(label);
        trace("  hasOwnProperty: " + (d.hasOwnProperty(key)?"true":"false <== !!PROBLEM!!"));
        trace("  in: " + (key in d));
        trace("  []: " + d[key]);
    };
test({}, "indexed by object");
test("string", "key is string");
test(0, "key is number");
test(true, "key is boolean");

结果：

indexed by object
  hasOwnProperty: false <== !!PROBLEM!!
  in: true
  []: true
key is string
  hasOwnProperty: true
  in: true
  []: true
key is number
  hasOwnProperty: true
  in: true
  []: true
key is boolean
  hasOwnProperty: true
  in: true
  []: true