To support site configuration, JS9 tries to load a json file called
js9Prefs.json from the same server on which the main
js9-[version].js file resides. The file will be looked for first in
the same directory as the web page and then in the js9 install directory.
NB: the JS9 Node.js helper still utilizes the js9Prefs.json file. Please ensure that the properties defined in these two files are consistent.