Can you give an example? If I used this to load HTML into a 3D environment every user could have the same virtual screen size.

Every browser renders HTML slightly differently, so you could render some arbitrary HTML into the canvas and then read out the pixels.

I see what you mean. Isn't that already what the user agent tells you?

	▲	turnsout 7 days ago \| parent [-]
		Oh my sweet summer child. The game of cat and mouse is so much more vicious than that.