For testing purposes you may need to perform local ajax calls against the filesystem. If you are running the pages throw a web server, everything should work as normal, but if you are accessing the local filesystem directly you may need to adjust the security settings in your browser.
( see: http://kb.mozillazine.org/Security.fileuri.strict_origin_policy )
( see: http://www.chromium.org/developers/how-tos/run-chromium-with-flags )