I've gotten a lot of question about detecting different devices in QlikView, and I've created man extensions that were somewhat specific in targeting devices. So what I've created now that is a way more simple extension (and way more flexible for the QV developer) is a document extension that simply detects the device information and sets a QV variable to hold that information.
Detecting a browser's userAgent is very simple and a long ugly string will be returned with a variety of information. Go to this site to see generally how it will look:
Within that string you'll be able to find your OS as well as browser. Also, if you're viewing on an iPhone, for example, you'll see the word "mobile" in there.
So once this variable is set, do whatever you want with it. You can check to see if it's specifically an iPad, an iPhone, runs Android, etc.
The variable the extension is setting is called vDevice