Changing Unity's resolution in a browser?

I wonder if anyone has explored the restrictions or opportunities of running Unity in a browser with regard to dynamically changing the Unity window?

For example what is the controlling mechanism for the dimensions of the Unity window in a browser? Is it based on the html width/height tags or is it forced by the settings from the editor during creation? If I use html tags that are less than the editors resolution settings will Unity crop or resize to match?

Can the resolution be over-riden at runtime in a browser? I don't mean just going fullscreen, which appears to switch the desktop resolution to match the Unity window, but can you go full screen to whatever the users current desktop resolution is?

Can you set a resolution that is larger than the users desktop? For example if I want to get a high quality capture of the 3D scene for offline use?

Cheers

The window width/height is determined by the html. The full-screen size is determined by the standalone resolution, though it will never exceed the desktop resolution. (So using something like 9000x9000 will essentially force desktop resolution on any computer.)