When watching HTML5 videos on Tor Browser, is it dangerous to go full screen?
Can this be used to find out my screen resolution?
Especially wondering this for Youtube.
Youtube does a lot of crazy stuff. It is not your normal HMTL5 video tag, there was actually some beta feature where you can try to ask google to send you only with Ogg+Theora, but then many of the videos show up as unavailable.
If you look at the video tag itself http://w3schools.com/tags/tag_video.asp You will notice that the tag provides the dimentions, but there is no way to set different URLs for player sizes. So when you go full screen with a true HTML5 site it is still the same URL that is being loaded, and the resizing takes place on your local machine.