Unfortunately a Javascript solution wouldn't work. JS runs in the context of your browser, as a child of your browser. So yes, it can close the browser instance, but then the process is dead so it can't do anything. And JS doesn't have the capability to make system calls, so it can't open a new instance before closing the current one.

Come to think of it, it might be possible to write a small Java applet to open a separate browser instance, but the user would have to explicitly allow the applet to do this... and it's way more trouble than I would go to in your place.

LAI
:eof