Make a callable() object in all browsers and Node.js

gistfile1.js

if (!Object.__proto__) {
  var sandbox = function () {
    // create an <iframe>
    var iframe = document.createElement("iframe");
    iframe.style.display = "none";
    document.documentElement.appendChild(iframe);
    return frames[frames.length - 1];
  }

  var iframe = sandbox();
  iframe.document.write("<script>parent.Callable = function (F) { var C = function () { var obj = function () { C.prototype.call.apply(this, arguments); }; F.apply(obj, arguments); return obj; }; C.prototype = Function.prototype; return C; }; parent.Callable.prototype = Function.prototype;<\/script>");
} else {
  this.Callable = function (F) {
    var C = function () {
      var obj = function () {
        C.prototype.call.apply(this, arguments);
      };
      obj.__proto__ = C.prototype;
      F.apply(obj, arguments);
      return obj;
    };
    return C;
  };
}

var API = Callable(function () {
  this.prop = 'and a property value .prop';
});
API.prototype.call = function (arg) {
  console.log(arg);
};
API.prototype.boss = function (arg) {
  console.log(arg, this.prop);
};

var a = new API();
a('.call() invocation');
a.boss('.boss() invocation');

Heh, I just wrote something very similar (https://gist.github.com/4636379, CoffeeScript) and found that. Your solution for browsers without proto is very clever, nice work!

Shouldn't you create a separate sandbox for every callable tho?