Would it be possible on a Linux box to show a browser window with only the content window, meaning no border around it, neither menu bars etc?
We need this for a big concert screen where a client program runs in the background. In front of that window we need to show a webpage, and it must look like the two programs are as one.
Use Firefox and press F11, that should do the trick.
Edit: This will only show the browser in Full-Screen mode, and you can't see anything else. I am not sure this is what you want.
try evilWM. According to this site it's very minimalistic and good for borderless stuff.
Run the browser on X11 WITHOUT a window manager and in fullscreen mode. Used to work with Galeon, probably can be made to work with other well preconfigured Gecko derived browsers.
Browser
Linux window managers (especially KDE) have additional options for border and menu configurations for all/any programs separately, it's called "Window behavior":
http://userbase.kde.org/images.userbase/3/39/Config-win-behavior.png
http://www.ghacks.net/2010/02/20/window-specific-options-in-kde-4-4/