Invalid procedure call or argument in Javascript on IE8

I have a little problem on IE8. Everything works fine on Chrome and FF.

I have a function like this:

var Dog = function(){};

and I'm able to do this, of course:

new Dog();

I open a popup window and I try to do this:

new window.opener.Dog();

and now, only in IE, I开发者_JAVA百科 get:

Invalid procedure call or argument

Does anyone knows if it is possible to create an instance of a function defined on the parent window?

Thanks.