I'm developing an application that rendered inside iframe using subdomain. Main apps using url: a.mydomainame.com, and iframe apps use url: b.mydomainame.com. In order to make overlay/masking for the whole apps, I have to set the document.domain="mydomainame.com". When I try to use AJAX(a4j), Front-End(UI) never receive any results from backend(server), so UI keep showing the loading icon. When I try to debug on server side, I can see the process already finish, but no data passed back to UI. I did try to reload manually the page by right click, This Frame > Reload Frame, then I can see the data is being rendered. This problem only happen on firefox, but working fine in IE. Any solution for this?