So it works as long as it's not added to the Home Screen? What's the Home Screen? Like your homepage when you first open the browser? As said in my previous replies I do not have an iPad so I of course can not test it on one and thus is not supported (in other words if it works it works and if it doesn't then it doesn't). Simulator won't help with this. It has nothing to do with the browser or the OS, but entirely an issue with the device it self.

Nope it's not an issue with the device itself, and you cannot avoid hundreds of million of users like this when windows is simply disappearing for most of our visitors.

It has nothing to do with Windows. It works fine on OSX, etc... It's a Mobile device issue. I've already told you I do not support Mobile as I do not have a Mobile device except an Android phone to test any of this on properly. Apple does not provide an official simulator for Windows so that is not an option either. If you know of any Windows based simulator (and is free; preferable open source as well) and can confirm it can reproduce your issue then I can investigate further.

When we try to connect, the social network window is loaded, then authentication is correctly performed (twitter for instance), then the social network window is closed, and then a blank window appear with only the html code as attached :

There should be two windows for the entire process. One is the website it self where you clicked the button and another is the authentication window. The first window should redirect or refresh after the authentication window closes. If the first window is gone then there's nothing I can do as it's not keeping the parent window.

Does it help tracking the problem ?

Unfortunately no as there's nothing to indicate a problem. The window is just an empty window. What is the URL of the empty window?

Did some quick searching and it looks like by adding it to your Home Screen it's adding it as a WebApp. When you navigate with the browser it's just using Safari. It's not a WebApp so it's not going to work as a WebApp; you need specific coding for a WebApp to work properly, which I have no way of testing. Plus the WebApp instances can't cross communicate through JS so it wouldn't work anyway. The only solution would be for it to be an inline popup that used iframes to load in the social sites, which they won't allow me to do and would just create cross domain issues.

That just handles the closing of the pop up. The parent window holds the code to redirect if it was successful or not. An entirely new usage would need to be implemented without the popup as its needs to do a 3 stage redirect instead of a popup. For WebApps it needs to redirect to authentication, redirect after authentication back to the site for token exchange, then after token exchange redirect to register/login. Again, I don't have an iPad or iPhone to test this on so I will not be implementing it. You're welcome to try messing with that code, but you need to have agent checks to test for mobile device or not so it behaves normally in regular browsers.