Can I programmatically connect to a hotspot wifi without user intervention?
I have the password stored in an app and the clients will not able to see it.
Since this is in the Rails forum I'll assume you're talking about a website using JavaScript. The short answer is "No". JavaScript is sandboxed to avoid giving viruses precisely the kind of control you're asking about. Altering a user's network settings via a website would be a very dangerous road to go down.