How does Google know my Computers's name?

Question

I was entering my Google account recently and noticed that not only did it say which browser I was currently using - it also knew the exact name of the computer I was using. How is Google able to fetch these informations?

I have been browsing the internet for javascript methods that should give me computer name or similar - but I am sure that Javascript is not able to read these data. If for anything, the site should maybe contain a small java application that executes and fetches the data, but that would usually require for me to accept that java is running in the browser by clicking a modal opening box.

Then I thought maybe they executed some C code in the browser - but how do they do it and access data outside the browsers "sandbox"? A third theory I have is that when I installed the Google Chrome browser, it was able to pass along these details - but it didn't make sense neither when I note that it also knows my iPads exact name though I haven't installed any google applications on my ipad at all. (neither google maps, gmail, chrome or anything).

UPDATE 01/25/2016

I have given this some extra thought and seemed to stumble across something else. I went through possible solutions using node.js or Flash to do the same, but I recalled that Google writes everything in Python, which made me think if it was simple enough using Python. I found this post: How can I use Python to get the system hostname? and thought that this might be a way for Google to it. I don't know if this is still achievable when you are writing a website and if this is a browser-based method as well (mind you I am not Python programmer at any level).

Answer 1

I did some testing. I have 2 Google accounts, and what I found was that on my main account (which I use with Chrome), Google knows my computer name. On another account, I am logged in with Edge and Firefox, but neither of them show my computer name. It was not until I logged into the Chrome browser ITSELF (not the Google page) as a Chrome user that my second Google account showed the browser I was using.

I verified this on my laptop: I logged in with my second account into the Google website on a new user, which didn't update the computer name on either device in the security settings. Once I logged into the Google Browser with that account, it showed my computer name. So it looks like because you're logged into Google Chrome, Google knows your computer name.

Note that Google using a sandbox does not make any difference for this. It is trivial to find your computer name, all it takes is hostname in a command prompt.