If you get an alert, then something didn't work.
Check out the console to see what's going on - failure to load cordova is expected
Don't forget to accept your browser request to store data on the local computer!
If this file is opened in Chrome from a "file://" url, run Chrome with the following flags: --allow-file-access-from-files --allow-file-access in order to avoid a security error.
Otherwise run the page from a web server - More info