This is to help who is having trouble with Captive Portal by Zeroshell and Apple devices.
After upgrade to iOS6 (before this release I never found any problem), a customer encountered some problems after typing credential on Captive Portal, because after submit he received a white page without any login done.
To solve this issue, it is simply needed to upgrade to ZeroShell b15 or b16, using scripts available on the forum. Please note you have to upgrade each single version (you cannot directly upgrade for example from b12 to b15, but you have to install b13 and b14 before).
Once installed b15+, go into Captive Portal > Gateway and, on the right, e into “Gateway Parameters” box hit the “PopUp” button.
Here you can add which browser will NOT use popups to authenticate. If empty, you can simply copy and paste this list: