chrome/common/extensions/docs/examples/apps/background-simple/README

This example demonstrates background window functionality in a hosted app.
To run the app, you first need to edit it and install it:

1. Put index.html and background.html in a directory where the HTTP server
   can find them.

2. Edit manifest.json. Search for SOME_, replacing the text with URLs
   pointing to the launch page (index.html) and to the directory where
   index.html and background.html live.

3. Install the app from manifest.json. You can use the Load unpacked extension
   button on the chrome://extensions page.

Once the app is installed, you can launch it by clicking its icon on the
New Tab page.

For more information, see the documentation:

   http://code.google.com/chrome/apps/docs/developers_guide.html