How to close a popup in Internet Explorer?

Question

I need to query a third-party site with ajax. To do so I need cookies, which I retrieve by loading the site's page in a hidden frame. However, I just saw that IE (at least 11) blocks cookies set in frames if the site doesn't provide a P3P policy.

To work around that, I initially thought opening the site in a popup then closing it. But it seems impossible, as the return value of a window.open is null if the url is not from the same domain.

Here's some test code:

var foo = window.open(url);
setTimeout(function(){
    foo.close(); // fails in IE as foo is null if url is 3rd-party
}, 2000);

I've seen restrictions, such as Window.close can only close windows created with js (or asks confirmation), but I haven't seen anything regarding cross-domain such as my case. BTW, there's no issue with FF and Chrome. Is there any way to do that?

Answer 1

Ok, so I finally got it. It has nothing to do with same origin policy. The catch is I was testing the above code in a page accessed through a http://localhost/ url. If I access the same page with http://127.0.0.1/ instead, the foo variable is not null and the popup can be closed.

If anyone has any idea why some restrictions in IE apply on localhost and not on 127.0.0.1, you're welcome.