HTML5: manipulating browser windows

Does HTML5 give the ability to directly manipulate browser windows (like switching a window to the foreground, closing it, getting its name and contents, etc) even if my window doesn't "own" them?

I realize this is a security risk, but I would like to at least do this on my local system wher开发者_高级运维e I can provide privileged permission to a script if necessary.

Your best bet is to make a Firefox add on or Chromium add on. It's the only way you are truly going to be able to gain access to the things you are wanting access to.