Cakephp 3.0, get id from URL when using on IFrame

Question

I am using CakePHP project in IFrame. I have a query string bid in the URL.(Eg: http://localhost:8765/?bid=Mjc). Initially I use $_GET['bid']. Later I have used $this->request->query['bid'].

The last method I used is working fine when I call the URL directly into the browser. But when I call the URL from IFrame(Eg: <iframe src='http://localhost:8765/?bid=Mjc' id='WidgetFrame'>), the $this->request->query array comes empty.

Could any one please suggest me best method to get bid from URL.

NOTE: Using $_GET['bid'] working on both Browser and IFrame.

Thanks.