I need to identify different browser users as well as different browsers.

For example, if one customer opens Chrome user account A to do something on my website, and opens Chrome user account B and also does something, then I need to know he moved on to a different user.

Also, if he opens my site with the phone, then I need to know he changed to another different browsing environment.

Hence, I want to know if there is a unique identifier for browser account (A or B), browser type (safari or chrome), or platform (PC or mobile), that is accessible with JavaScript.

I tried to random-generate cookies as they are not shared between different users. But there still are risks that this random generation can make identical results. Hence, it is not 100% error-proof.

Is there a UDID-like thing for different browser users / different browsers / different platforms that javascript can access? Or how can I make it?