Do the website really see your browser window size?

Browser inner screen size can bee seen by ip-check.info when I Disable JavaScript, and then I checked Work offline from the File menu of Tor browser, then tried to resize the browser window, the browser inner size is still changing even if you cut off your internet connection!

So I want to ask is the website checking your browser windows size all the time? Or only you can see the browser windows size all the time? Or the website check it when it have internet active?

When I visit ip-check.info with JavaScript enable, the screen size of browser not changing when you resize it, is this the size Tor Browser sending to website? Or it is still only for you?

I want to ask, how to resize of browser size to other normal screen display should? Like, when you maximize the Firefox window, when you back to the default windows size. And need to zoom or shrink the fonts and page?

 

It's one of the many web browser fingerprint issues: https://panopticlick.eff.org/

Right, but nothing is being sent to their side- it's all on your end. You still have their test loaded.

It's like if you downloaded a game and then disconnected from the internet. The game still runs, because it's saved to your hard drive.

 

https://panopticlick.eff.org/ couldn't detect the inner size of Tor Browser with Javascript off, that is different than ip-check.info, which is the real case?